Category Archives: Chokepoints and Littorals Week

There Are No Strategic Chokepoints

Chokepoints and Littorals Topic Week

By Captain Jamie McGrath, USN (ret.)

Keys to the World

Naval theorist Milan Vego opens a chapter on chokepoint control with a quote from British Admiral Sir John Fisher, who stated that there are “five keys to the world. The Strait of Dover, the Straits of Gibraltar, the Suez Canal, the Straits of Malacca, and the Cape of Good Hope. And every one one of these keys we hold.”1 Fisher spoke from an Anglo-centric view, but his point is evident that control of key chokepoints equated to control of national strategic interests. But a century later, with the technological advances in weapons and sensors, and the interconnectedness of the global economy, can such a claim be made today?

There are over 100 straits where international interest in the free flow of trade transcends the interests of the nearby littoral states. Not all of these maritime chokepoints are of equal importance. Military strategists often speak as Fisher did of strategic chokepoints, believing them to have significant geopolitical value and act as epicenters for maritime strategy, where the control of which is considered vital for success in maritime conflict. But are these chokepoints truly strategic? Does the success of a nation’s maritime strategy actually hinge on the control or loss of control of these narrow seas?

Perhaps the strategic value of any given chokepoint is overstated because the ability to truly “control” these chokepoints is significantly degraded in the current maritime threat environment. The focus should instead be placed on strategic seas, and not the connectors between them.

Strategic Versus Operational Significance

Before scuttling the idea of strategic straits, there should be a common understanding of the difference between the strategic and operational importance of maritime geography. Maritime strategy is the science and art of using all naval and non-naval sources of power at sea in support of the national military strategy, with military strategy being “the art and science of using or threatening to use military power to accomplish the political interests of a nation…”2 The 2018 National Defense Strategy calls for:

“A more lethal, resilient, and rapidly innovating Joint Force, combined with a robust constellation of allies and partners, will sustain American influence and ensure favorable balances of power that safeguard the free and open international order. Collectively, our force posture, alliance, and partnership architecture, and Department modernization will provide the capabilities and agility required to prevail in conflict and preserve peace through strength.”3

The focus on lethality, resilience, and lethality within an alliance and partnership architecture, combined with “lethal, agile, and resilient force posture and employment,”4 and “a global strategic environment [which] demands increased strategic flexibility and freedom of action,”5 indicate that fixed geographic positions like chokepoints have reduced strategic relevance in U.S. strategy.

Naval operations are defined as the “theory and practice of planning, preparing, and executing major naval operations aimed at accomplishing operational objectives.”6 While operational objectives are chosen to achieve strategic ends, there often are multiple operational options to a support strategy. The operational value of a chokepoint tends to be temporal and depends on the other operational factors of time, space, and force of the particular operation. A chokepoint with high operational value may have limited or no strategic value if other options exist to achieve the national political objectives.

Traditional Methods of Sea Control

The control of chokepoints has long been a primary way to control access to a given body of water. Revisiting Fisher’s assertion that there were five keys to the world, control of key straits meant control of the flow of global maritime traffic and, therefore, the strategic interest of most maritime nations. Warships and merchantmen during the age of sail depended on the prevailing winds for reliable propulsion and shore bases for routine resupply. These trade winds and shore bases funneled ships through specific shipping lanes, many of which transited the key chokepoints Fisher identified. Since transit of these chokepoints was essential, controlling them guaranteed control of merchant shipping and warship movement.

The emergence of steam propulsion removed reliance on the trade winds, but increased dependence on the shore bases that had been established in the age of sail, which were starting to serve as coaling stations. Thus, in Admiral Fisher’s time, his assertion was correct. But since World War II, dependence on shore basing for resupply has diminished. The U.S. Navy perfected at-sea replenishment during World War II, and merchantmen have significantly increased their unrefueled range, both of which reduced the reliance on shore stations and subsequent dependence on specific shipping lanes.

Chokepoints simplify several operational and tactical aspects of naval warfare by concentrating forces. This, in turn, limits the challenges of scouting and screening, because less sea space must be scouted and screened. The avenues of approach to the chokepoint are limited, so the party that controls the chokepoint can concentrate forces or make better use of limited forces available.

Admiral Tōgō Heihachirō’s defeat of Russia’s Second Pacific Squadron at the Tsushima Strait demonstrates how chokepoints simplify scouting. Togo did not know when the Russian fleet would arrive, nor did he wish to search for it in the open ocean. But he did know that the Russian fleet had to pass through the Tsushima Strait to reach its base at Vladivostok. This allowed Togo to concentrate his scouting force of cruisers in the strait and consolidate his battle line inside the Sea of Japan. But what if the Russians had entered the Sea of Japan through the La Pérouse Strait, Tsugaru Strait, or Strait of Tartary? In the 1890s, the limitations of coal-fired steam plants meant that traveling the extra 1000 or more miles without a coaling station made the Tsushima Strait the only choice. Today, however, at-sea logistics provide naval forces greater flexibility in entering strategic seas.

Changing Military Value of Chokepoints

Historically, chokepoints held strategic military value partly because they forced ships to transit within range of the weapons and sensors posted there, and made movements more predictable. Into the second decade of the twentieth century, optical sensors and coastal guns limited that range to or just beyond the horizon. Technological advances over the intervening century expanded that range immensely. First, aircraft extended scouting range, then, as aircraft improved, expanded the striking range of weapons well beyond the chokepoint’s horizon. The introduction of radar further enhanced scouting and early-warning capabilities, and space-based surveillance now allows for the searching of vast ocean areas independent of geographic chokepoints. The missile age added over-the-horizon, ship-killing weapons, with anti-ship ballistic missiles (ASBM) marking the ultimate long-range strike capability.

Holding a chokepoint serves two fundamental purposes, one rooted in sea control and the other in sea denial. The sea denial case, often a strategy of the weaker navy, holds that by controlling the chokepoint, an adversary cannot access the seas on its opposite side. As Vego points out, this is often part of a larger, major defensive joint/combined operation and maybe one of several elements of a national defensive strategy to either bottle up an opponent’s naval force in its own narrow seas, or prevent an opponent’s naval force from entering a narrow sea where it could threaten the defending nation’s territory.7 In the sea control case, control of the chokepoint theoretically allows one to use their naval forces at the time and manner of their choosing within the chokepoint and in the seas controlled by the strait. That is to say, if a nation controls a chokepoint, naval forces and maritime trade can pass through that chokepoint freely at the discretion of the nation that controls it.8

In the current maritime threat environment, controlling the land and water in the vicinity of the chokepoint no longer represents the exclusive manner to control it. The focus on strategic chokepoints may have held when the range of weapons was barely over the horizon, but today an adversary no longer has to control the geographic entrance to strategically important seas to deny their use. Space-based sensors and long-range missile firepower allow an adversary to effectively close, or at least threaten closure of, geographic chokepoints without the traditional need to hold the immediate surrounding land or seas. “Holding” a geographic chokepoint no longer guarantees the use of the seas on either side, nor does it ensure safe passage through the chokepoint itself. Therefore, the U.S. Navy would be better served to focus more broadly on its ability to control or deny strategic seas than the strategic chokepoints of ages past.

Changing Economic Value of Chokepoints

Another element that gives a chokepoint strategic value is the volume of trade transiting the strait. Traditionally, blockades and maritime trade warfare have used control of chokepoints to great strategic effect. Britain’s control of the Dover Straits, combined with the North Sea Mine Barrage, closed all maritime trade to Germany during World War I and contributed to the fall of the Kaiser’s government in 1918. During World War II, the failure of the Axis powers to seize the Suez allowed Great Britain to continue using the canal for resupply of its empire. Would such action have the same strategic effects today?

Vertical and horizontal charts showing locations and densities of mine fields of the North Sea Mine barrage, issued in November and December 1918, after the fields were completed. (Naval History and Heritage Command)

Today, high trade volume certainly gives a strait economic value because these chokepoints often represent the shortest route from manufacturer to market and thus the cheapest transportation cost. But is controlling trade through a strait a viable strategic goal? Chris McMahon argues that maritime trade warfare is ineffective in today’s global economy. Among the many reasons he presents, he notes that the closing of chokepoints has no real impact on global trade.9 One of the most-often mentioned strategic chokepoints is the Strait of Malacca because it handles so much of the world’s maritime traffic. But how would closing the Strait of Malacca affect global trade? It would impact Singapore’s role in the global shipping market, certainly. But would the global shipping network be severely burdened by having to transit the Sunda Strait or the Lombok Strait? Would there be a cost increase, yes, but once the market adjusts for the increased cost, shipping will find a way to make it work. 

Consider the wave of piracy off the Horn of Africa in the early 2000s, an area often discussed as a strategic chokepoint because of the volume of trade passing through the Arabian Sea. Shipping companies dealt with the insecurity of that maritime region in one of three ways – accept the risk and charge accordingly, arm themselves against pirates, or re-route ships around the Cape of Good Hope at increased cost and charge accordingly. In each case, maritime trade continued. Lord Fisher mentioned the Suez Canal as one of the keys to the world, but it has been closed on five occasions since it opened in 1869, including for eight years between 1967 and 1975. During that most recent closure, the cost of shipping around the Cape of Good Hope was markedly higher than the Suez route but presented no serious economic hardship to global consumers. Rerouting Pacific trade for a closed Strait of Malacca would have a similar minimal effect on the cost of global trade.10

Chokepoints Can Be Superseded

The demise of the strategic value of chokepoints is revealed by looking at some traditional strategic chokepoints of the past. One of Fisher’s keys to the world, British control of the Straits of Dover, seemingly kept Hilter’s Kriegsmarine bottled-up in the North Sea, much as it had the Kaiserliche Marine three decades before. But Germany negated the British advantage by conquering France and establishing bases in Brittany, unfettered by the Straits of Dover. To be sure, the straits still impeded access to merchant shipping and warship transit to the German homeland, but control of the strategic strait did not mean control of the German U-boats. Chokepoints can be bypassed.

During the Cold War, the water between Greenland, Iceland, and the United Kingdom – the so-called GIUK Gap – was a strategic chokepoint because Soviet ballistic-missile submarines had to pass through that gap to threaten the United States. The later development of longer-range submarine-launched ballistic missiles meant the submarines could remain in the Arctic to launch these weapons, thus limiting the strategic value of the GIUK Gap as a chokepoint. Chokepoints can be outranged.

The GIUK gap and major regional military bases. (Heritage Foundation)

Today, a resurgent China lays claim to the South China Sea (SCS) as its own internal waters. As discussed above, the Strait of Malacca has traditionally been a key to control of the SCS and, therefore, strategically important for trade between Europe and Asia. But the Strait of Malacca is not the only access route to the SCS, which can also be accessed through the much larger Luzon Strait and numerous passages through the Indonesian and Philippine archipelagos. The PRC recognizes this and has adopted control mechanisms that do not depend on control of the chokepoints, but instead focuses on long-range anti-access, area-denial (A2/AD) weapons and redundant fortified islands within the SCS.11

China’s A2/AD strategy in the SCS is important for two reasons. First, the assumption that physical control of a chokepoint guarantees use of the chokepoint is invalid in the face of PRC A2/AD weapons and sensors. Although the United States and its partner states may possess the land on either side of the Strait of Malacca, and have sufficient naval forces to patrol the strait, the PRC could nonetheless prevent free transit of the Strait of Malacca using ASBM and long-range anti-ship cruise missiles (ASCM). Furthermore, these long-range weapons based on the Chinese mainland or in the central SCS can contest the other straits leading into the SCS. Conversely, the reduced reliance of predictable trade routes for maritime traffic – both merchant and military – means they can easily bypass the Strait of Malacca if it were to be “controlled” by an opposing power.12 Chokepoints can be replaced.


The question then should not be “what are today’s strategic chokepoints?” but instead, “what are today’s strategic seas?” Control of chokepoints is only one of the ways to control a sea. Vego writes that there are two primary arenas of naval conflict: open ocean and narrow seas. While many characteristics differentiate the open ocean from the narrow sea, the predominant one is proximity to land.13 In narrow seas, the land influences many aspects of naval warfare, from the ability of naval vessels to maneuver to the threat from land-based weapons. As one moves further out to sea, maneuver space opens up and land-based threats dissipate, or so it would stand to reason.

The ability of naval forces to operate freely on the open ocean outside the threat of land-based weapons, whether missiles or aircraft, is greatly diminishing in the current threat environment. This, in turn, means an expansion of the areas previously considered narrow seas – even if not in all aspects. If the narrow seas have now broadened to cover a much higher portion of the world’s oceans, then the restrictive chokepoints once seen as strategic lose much of their relevance. 

There may be operationally compelling reasons to control a chokepoint, but their strategic value is greatly diminished in an era of space-based sensors and proliferating long-range missiles. Control of a chokepoint no longer means the “keys to the world” as it did in Admiral Fisher’s day. Expending the time and force to control a chokepoint will likely not result in the strategic advantage sought, and worse, could fix forces to a geographic location when mobility is operationally necessary. The U.S. would be better served exercising more agile and dynamic mechanisms of strategic sea control and sea denial rather than focusing on the obsolete idea of strategic chokepoints.

Captain Jamie McGrath (ret.), retired from the U.S. Navy after 29 years as a nuclear-trained surface warfare officer. He now serves as a Deputy Commandant of Cadets at Virginia Tech and as an adjunct professor in the U.S. Naval War College’s College of Distance Education. Passionate about using history to inform today, his area of focus is U.S. naval history, 1919 to 1945, with emphasis on the interwar period. He holds a Bachelor’s in History from Virginia Tech, a Master’s in National Security and Strategic Studies from the U.S. Naval War College, and a Master’s in Military History from Norwich University.


1. Quoted in Milan Vego, Maritime Strategy and Sea Control: Theory and Practice (Rutledge: London, 2016), 188.

2. Milan Vego, Maritime Strategy and Sea Control: Theory and Practice (Rutledge: London, 2016), 2.

3. James Mattis, Summary of the 2018 National Military Strategy of the United States of America (US Department of Defense: Washington, DC, 2018), 1.

4. Ibid., 7.

5. Ibid.

6. Milan Vego, Operational Warfare at Sea: Theory and Practice (Rutledge: London, 2017), 1.

7. Vego, Sea Denial, 301.

8. Vego, Sea Control, 188-9.

9. Christopher J. McMahon, “Maritime Trade Warfare,” Naval War College Review: Vol. 70: No. 3 (Summer 2017), 29-34.

10. Ibid., 29-30.

11. Naval War College Professor James Holmes argues that considering PRC sea power, their entire military must be considered and not just the PLAN, see James Holmes, “Visualize Chinese Sea Power,” United States Naval Institute Proceedings (June 2018).

12. McMahon, “Maritime Trade Warfare,” 29-30.

13. Vego, Sea Control, 18-20.

Featured Image: August 6, 1988, Egypt: An aerial port bow view of the aircraft carrier USS FORRESTAL (CV 59) transiting the Suez canal. A formation of crewmen spells out”108″on the bow to signify that the ship has been at sea for 108 consecutive days. (Photo by PH2 Buckner, USN/U.S. National Archives)

Mine the Littorals and Chokepoints: Mine Warfare in Support of Sea Control

Chokepoints and Littorals Topic Week

By Major Brian Kerg, USMC

A Game of Go

The primary objective of the game of Go is the control of territory. Players do this by laying stones in ways that maximize the connectedness of their own pieces, deny connectedness of enemy pieces, and in ways that mark out the most territory on the board. Open spaces next to any stone are called ‘liberties,’ and marks opportunity for connection or disconnection. Placing your stone on an enemy stone’s liberty cuts off your opponent’s options.

It is possible to capture enemy stones by taking away the last liberty of any group of connected or individual stones. Competitive stone laying where capture is the likely outcome is equated to a ‘fight.’ Novice players often focus on winning a fight with their opponent, as they spend several turns laying stones in ways that allow them to completely surround their opponent’s group. But the overall goal is not maximizing the amount of stones captured. Preoccupation with capturing stones will lead a player to lose momentum and initiative while their opponent spends those turns carving out territory, maximizing strategic control of the entire board, and ultimately winning the game.

This is the challenge the sea services face as they pursue the goals of the 2018 National Defense Strategy.1 As the United States embarks on a period of great power competition with potential adversaries, the Navy and Marine Corps are focused on achieving deterrence by denial through means of sea control and sea denial. While naval forces must be able to win a conventional conflict should one break out, the risk of escalation to a nuclear exchange puts a premium instead on convincing adversaries that conflict isn’t worth the risk. Defense planners seek this objective by constricting enemy maneuver and decision space, and by canalizing opponents toward de-escalatory off-ramps. While the risk of war is present, the goal is not to capture or kill enemy forces – it is instead to control territory to obtain a strategic victory without fighting – Sun Tzu’s acme of skill.

The littorals are home to key maritime terrain that will define this battle for control of the global commons. To date, the sea services have focused their efforts on developing mutually reinforcing operational concepts that will achieve sea control and sea denial in this space. Distributed Maritime Operations (DMO) seeks to mass effects without massing forces, mitigating the vulnerabilities of U.S. Navy ships at the outset of any potential conflict by placing them as stand-off forces outside of an enemy’s Weapons Engagement Zone (WEZ) until threats have been reduced or sea control is achieved.2 Sea control will be initially achieved by Expeditionary Advanced Base Operations (EABO), which will place Marine Corps teams as stand-in forces to persist forward inside the WEZ, where combinations of mobile sensors and shooters will deny enemy freedom of action in the maritime domain.3 With enemy A2/AD capabilities checked by stand-in forces, stand-off forces will once again enjoy freedom of maneuver in the area of operations. When applied to archipelagic defense, such as across the first island chain, these concepts are inherently about imposing high-threat chokepoints on an adversary from the littorals.

While bold and full of potential, EABO and DMO possess their own gaps. If naval forces were projecting the power of EABO and DMO on a Go board, or oban, there would be points where they would lack connectedness, and where an adversary would maintain liberties. To better explore means by which strategic chokepoints in the littorals can be controlled, the sea services must revitalize mine warfare.

Naval mine warfare (MIW) has played a significant role in every major American military conflict.4 If employed in support of sea control strategies under development by the Navy and Marine Corps, and should its full potential be leveraged by emerging technologies, MIW can serve as the lynchpin for deterring aggression in the maritime domain, and if necessary, for defeating adversaries at sea. 

Where is Mine Warfare?

As sea control concepts, EABO and DMO are incredibly promising. They have generated great attention and energy from national security specialists and military thinkers, resulting in a high yield of thought pieces that have informed official military publications. This conversation has mostly focused on the integration of naval forces in support of DMO and EABO, new ways to employ existing capabilities for sea control, and what new capabilities need to be acquired or developed to provide sea denial.

But one topic that has not seen nearly enough discussion is the application of MIW in support of deterrence or denial. Most glaringly, official sea service documents are silent on the subject of MIW’s role in modern naval strategy. A Design for Maintaining Maritime Superiority 2.0, which was revised explicitly to align with the 2017 National Security Strategy and 2018 NDS, does not even include the word ‘mine,’ let alone any MIW related subjects.5 The Littoral Operations in a Contested Environment concept passingly mentions the need to consider command and control operations for Navy mine warfare capabilities, and only mentions MIW twice more but in terms of mine countermeasures, not Navy MIW employment.6 All other official sea service publications are similarly glib on the topic. The only solid connection between the potential for MIW in reference to deterring China is made in a 2015 Foreign Affairs article discussing archipelagic defense, years before the release of the current NSS and NDS.7

The absence of mine warfare in these discussions should be shocking to maritime strategists given the incredible historical utility of MIW. Mines have damaged or sunk more ships over the past 125 years than all other weapon systems combined.8 The lack of consideration for MIW preceding its decisive employment in America’s wars is the repetition of an old tune. To take one example, prior to the start of the Second World War, the U.S. Navy hadn’t built a minesweeper in its history.9 By the war’s end, the U.S. had laid thousands of mines which sank hundreds of Japanese ships, critically disrupting Japanese maritime shipping.10 After years of stilted progress in the Vietnam War, the mining of Haiphong Harbor was a critical factor in compelling America’s enemies to start negotiating for an end to the war.11

September 17, 1992: RADM Raynor A. E. Taylor, commander, U.S. Naval Forces, Central Command, center, briefs ADM David E. Jeremiah, vice chairman of the Joint Chiefs of Staff, as Jeremiah studies a mine during his tour aboard the miscellaneous flagship USS LA SALLE (AGF-3). (National Archives)

Today, the pendulum has swung back in the direction of limited consideration for MIW. The U.S. Navy has only two types of mines in its inventory, the aircraft-laid Quickstrike and the Submarine-Laid Mobile Mine (SLMM). And despite a military technology renaissance that is characterized by autonomous systems, human-machine teaming, and the Internet of Things (IoT), scant energy has been directed toward pairing disruptive technologies with MIW, let alone for the purposes of sea control or sea denial. The most recent Navy-sponsored innovations in MIW, the Quickstrike-J, Quickstrike-ER, and the Hammerhead, only allow for more precise deployment of existing mine capacity.

MIW can critically reinforce control of key maritime terrain, particularly at strategic chokepoints in the littorals. This is possible by understanding the potential that MIW brings to the sea control and sea denial strategies under development by the Navy and Marine Corps, and by employing current and emerging technologies to support the new and repurposed force design.

Employing Mine Warfare in Sea Control

A critical aspect of sea control strategy is the control of key maritime terrain. This includes any area, ashore or at sea, that when controlled enables influence over the maneuver of others conducted in, on, or around that area. Imagine a small, concealed team of Marines operating from an Expeditionary Advanced Base (EAB) somewhere in the South China Sea, armed with a long-range precision fires system with a threat range of 300 nautical miles. By virtue of its location and the influence its weapon system has on maneuver around its location, this EAB force is occupying key maritime terrain and executing sea denial. By the same token, a U.S. Navy surface ship with a threat range around the Straits of Malacca would similarly provide sea control at key maritime terrain.

In the sea control envisioned by naval planners to execute the 2018 NDS, most writers have described a series of interlocking, mutually reinforcing threat envelopes presented by naval forces, comprised of teams of Marines ashore operating out of EABs, and small, distributed Navy platforms afloat.12 Used in the context of deterring China, such archipelagic defenses would provide the U.S. and its allies with significant influence over areas such as the South China Sea and East China Sea, limiting Chinese freedom of maneuver, providing a check against Chinese A2/AD, and providing entry for U.S. stand-off forces. While highly promising, the concepts are largely reliant on the deployment and persistence of naval forces in threatening forward areas, providing a vulnerability that adversaries will undoubtedly seek to exploit. In this construct, the enemy maintains liberties.       

This is where mine warfare can fill the gap, and provide stand-in forces with significantly enhanced flexibility and greater ability to control the sea. Used in concert with the sea control concept described earlier, naval mines can expand and more robustly interconnect the threat envelope presented by naval stand-in forces, and fill in the gaps between forward archipelagic defenses.

An overview of stand-in and stand-off force employment, where mines could reinforce force posture at the seams of archipelagic defense. (credit: Thomas Mahken, et al/CSBA)

Imagine two EABs in the South China Sea. The sensors and shooters they employ provide some span of sea control, but those forces are targetable and the control they provide is dependent on their ability to sense and shoot. If these two EABs were connected by a series of mines, one of which also pressed itself forward of the EABs, not only is their control reinforced, but they also have a kind of picket that simultaneously provides sea control and force protection. If they were stones in the game of Go, they would have attained connectedness.

Further, mines offer more than a way to reinforce emerging force design concepts that support sea control, but might serve as a primary means by which to establish sea control and denial. Viewing this maritime strategy as deterrence in depth, stand-off forces are farthest out from our key maritime terrain until conditions are right. Stand-in forces are the next layer forward, persisting inside the WEZ and providing some level of sea control and a check against A2/AD. Finally, mines employed by stand-in forces are the most forward projected capability, providing sea denial and pressing enemy naval forces against the wall.

If this were a game of Go with the South China Sea as the board, U.S. mines could serve as the lynchpin in this series of stones that connect key maritime terrain across Singapore, the Riau Islands, the Spratly Islands, the Philippines, and through the Ryukyus toward Japan. Having occupied all of the opponent’s liberties, we gain control of the greatest amount of territory, deny the opponent options, and have the greatest leverage as the game unfolds.

Employing Mines for Sea Control in a Contested Environment

The final challenge is employing mines in strategic chokepoints in a contested environment. Adversaries will not idly stand by while U.S. naval forces deploy mines and restrict their freedom of maneuver. While existing mine deployment methods provide some capability, they are hardly ideal for an environment of competition, or where the first goal is deterrence rather than outright conflict. Thankfully, current and emerging technologies offer a plethora of means by which mines can be employed per the above framework.

Commander Timothy McGeehan and Commander Douglas Wahl (ret.) ably described potential applications of the Defense Advanced Research Project Agency’s (DARPA) Upward Falling Payload (UFP) program. DARPA developed the UFP to provide distributed, unmanned containers that could lie on the ocean floor for years at a time, providing materiel on demand in maritime theaters across the globe. McGeehan and Wahl envisioned applying the UFP to create a minefield on demand, replacing materiel with mines.13 Taking this a step further, and deliberately in line with DMO and EABO concepts, this capability could instead be deployed well before tensions escalate with potential adversaries, and should the need arise, be employed by naval stand-in forces who could use distributed command and control systems to maneuver these minefields wherever they would best support sea control and denial requirements. Further, the knowledge that such an asset could create a stranglehold in key maritime terrain would further deter aggression and escalation among adversaries.

Upward Falling Payload concept (DARPA graphic)

While promising, the UFP has its own vulnerabilities, and such mines may be detected and swept by adversaries. Another method of deploying maneuverable minefields is through a modification to the current mechanism used for deploying the Quickstrike-ER Mine. Currently, the Quickstrike-ER is dropped by an Air Force B-52 bomber, and moves onto target with an attached Joint Direct Attack Munition (JDAM) kit. While this provides a shallow-water mine that can be deployed outside of enemy anti-aircraft fire range, the Quickstrike-ER cannot be moved to another location. By combining the Quickstrike-ER package with that of the UFP, we can provide a maneuverable minefield that can be deployed on demand, that can be controlled by naval forces, and maneuvered as needed to best support sea control requirements.

Another method of deployment and employment of mines is by modifying the Expeditionary Mine Counter Measures (ExMCM) company, training and equipping it instead to execute mine warfare in key maritime terrain. The ExMCM company is trained to employ unmanned systems for the purposes of executing the MCM mission. While usually deploying its systems from rigid hull inflatable boats (RHIB), they recently validated the employment of Zodiac combat rubber raiding craft (CRRC) to conduct MCM in a clandestine environment.14 Pursuing this and similar clandestine insertion methods, a newly formed Expeditionary Mine Warfare (ExMIW) company could instead emplace and control fields of naval mines at key maritime terrain, in support of sea control and denial. Alternatively, Marines training for EABO might add this task to their mission profile.

Panama City, Fla. (May 14, 2016) — Engineman 2nd Class Jonathan Lavoie (left) and Aerographer’s Mate 1st Class Christopher Kyall (right), assigned to Mobile Diving and Salvage Unit 2 (MDSU) Unmanned Systems Platoon 204, lower a Mark 18 Mod. 2 unmanned underwater vehicle into the water during an Expeditionary Mine Countermeasure (ExMCM) certification exercise. (U.S. Navy photo by Mass Communication Specialist 2nd Class Charles Oki)

With ever increasing flexibility provided by automation and human-machine teaming, the possibilities for deployment are almost endless. While the sea services can be solution agnostic, the end state is a maneuverable naval mine that can be controlled by naval forces operating at strategic chokepoints in order to control key maritime terrain, deter adversary action, and if needed, to win the maritime fight.

Mine Warfare: A Pillar of Deterrence by Denial

The potential of mine warfare in major military conflict is a matter of historical record beyond repute. Despite this, the utility of MIW is often ignored by American military planners between periods of conflict. The direction of the NSS and the NDS to prepare for great power competition demands more from naval leaders. The development of MIW capabilities in support of deterrence by denial must begin today.

While DMO and EABO provide the essential building blocks of sea control and denial, their deterrent power can be exponentially increased through the integration of MIW. Whether deployed between EABs by ExMIW companies, activated from UFPs and maneuvered into place as the situation dictates, or fired into shallow waters with the modified Quickstrike-ER and moved as required by C2 systems, MIW is the most promising yet underdeveloped capability for today’s maritime strategists. With these and similar innovations, the sea services can deliver on the promise of sea control and deterrence by denial, and win this global game of Go.

Brian Kerg is a Marine Corps officer and writer currently stationed in Norfolk, VA. He is a Non-Resident Fellow at Marine Corps University’s Brute Krulak Center for Innovation and Creativity. His professional writing has appeared in War on the RocksProceedingsThe Marine Corps Gazette, and The Strategy Bridge. His fiction has appeared in The Deadly Writer’s PatrolLine of Advance, and The Report. Follow or contact him @BrianKerg.


1. National Defense Strategy of the United States of America, (accessed 28 Jan 2020:

2. Kevin Eyer and Steve McJessy, “Operationalizing Distributed Maritime Operations,” Center for International Maritime Security (accessed 28 Jan 2020:

3. Headquarters, Marine Corps, “Expeditionary Advanced Base Operations,” U. S. Marine Corps Concepts and Programs,  (accessed 28 Jan 2020:

4. Joint Chiefs of Staff, Joint Publication 3-15: Barriers, Obstacles, and Mine Warfare Operations (Washington, D.C.: Joint Force Development, 2018), IV-1.

5. United States Navy, A Design for Maintaining Maritime Superiority 2.0, (Washington, D.C.: Office of the Chief of Naval Operations, 2018), 1.

6. US Navy and US Marine Corps, Littoral Operations in a Contested Environment (Washington, D.C.: Office of the Chief of Naval Operations and Headquarters, Marine Corps: 2017), 11.

7. Andrew F. Krepinevich, “How to Deter China: The Case for Archipelagic Defense,” Foreign Affairs (accessed 10 April 2020:

8. Joshua J. Edwards and Dennis M. Gallagher, “Mine and Undersea Warfare for the Future,” Proceedings 140 no. 8, (Annapolis, MD: USNI, 2014).

9. Paul Lund and Harry Ludlam, Out Sweeps! (London: W. Foulsham, 1978), 169–71.

10. US Navy Fact File, “US Navy Mines,” (accessed 10 April 2020:

11. William Greer, “The 1972 Mining of Haiphong Harbor: A Case Study in Naval Mining and Diplomacy” (Alexandria, VA: Institute for Defense Analyses, April 1997)

12. Brian Kerg, et al., “How Marine Security Cooperation Can Translate into Sea Control,” War on the Rocks, (accessed 10 April 2020:

13. Timothy McGeehan and Douglas Wahl, “Flash Mob in the Shipping Lane!”, Proceedings 142 no. 355 (Annapolis, MD: USNI, 2016).

14. Allan Lucas and Ian Cameron, “Mine Warfare: Ready and Able Now,” Proceedings 144, no. 357 (Annapolis, MD: USNI, 2018).

Featured Image: A mine detonates during exercise Open Spirit, August 31, 2017. (NATO)

The Assumption of Access in the Western Pacific

Chokepoints and Littorals Topic Week

By Blake Herzinger and Elee Wakim

“Having therefore no foreign establishments, either colonial or military, the ships of war of the United States, in war, will be like land birds, unable to fly far from their own shores. To provide resting places for them, where they can coal and repair, would be one of the first duties of a government proposing to itself the development of the power of the nation at sea.”–Alfred Thayer Mahan, The Influence of Seapower Upon History, 1660-1783

Since before the completion of the transcontinental railroad, the United States has determined that “American security, economic prosperity, and values would be fundamentally put at risk if a rival hegemonic power dominated the Pacific.” The United States has ensured this end by various ways and means since the defeat of the Spanish Empire in 1898. Given the vast distances between continental North America and the western Pacific littorals, the United States’ ability to project power and influence is necessarily based upon expeditionary maritime capabilities and globe-spanning military infrastructure. The cornerstone of this power projection complex in the western Pacific is forward deployed military forces, which are in turn enabled by the availability of proximate and friendly basing in theater. However, the ability of the United States to sustainably conduct expeditionary operations in the strategic chokepoints and littorals of Asia could crumble in the absence of the allied access it has come to rely on.

Access to the local, dual-use infrastructure the United States enjoys today is the result of years of sustained investment of all elements of American power to align mutually interested states into a network that allows the United States to project power from their shores. In recent years, these investments have been diffused across a broad number of states, such that the mortar is crumbling under a lack of recapitalization. This critically enabling influence of forward partners is waning as the PRC rapidly expands its influence, turning the political will of forward allies into strategic chokepoints of another sort.

The U.S. is therefore forced to consider whether those locations it relies on to sustain its overseas presence – whether by formal agreement or informal association – would still be available in the event of a military confrontation between the United States and China. How would this sudden loss of access affect how the U.S. fights as a force and projects power into the western Pacific?

While there are many detractors who will lampoon the proposition that the U.S. would ever be deserted by its overseas partners – perhaps citing years of historic partnership and common interest – it is important to ask if the U.S. is willing to bet the farm on this untested and assailable assumption. If not, what must the United States do in order to hedge against the loss of its heretofore unchallenged access to the western Pacific littorals and attendant infrastructure?

Access for What?

The American military presence in the Indo-Pacific largely reflects the vestiges of the Cold War and has its roots in the exigencies of conflicts ranging from World War Two to Vietnam. The United States has military relationships with nearly every country within the First Island Chain, ranging from limited partnerships to full military alliances. U.S. security cooperation plans keep most of those relationships on ever-increasing trajectories of investment, but this may be more a function of inertia than strategic acumen. American joint doctrine makes clear that the creation of access for U.S. forces is one of the three reasons for conducting security cooperation operations. This investment has created an unparalleled network of ports and airfields capable of supporting U.S. expeditionary operations and logistics in unchallenged environments (see Table 1).

Table 1: U.S. Military access arrangements among South China Sea littoral states
Country Acquisition & Cross Servicing Agreement (ACSA) Hosts U.S. Base or Rotational Deployments Routine Base Access
Brunei x
Indonesia x
Malaysia x
Philippines* x x x
Singapore x x x
Thailand x x

*In question after cancellation of U.S.-PHL Visiting Forces Agreement

As the United States and China continue to jostle for position, allies and partners are pulled in separate directions. The long-relied upon American security guarantee is confronted by China’s growing military and economic strength, and geographic proximity. Despite the deep history and genuine bonhomie between the U.S. and its security partners, this confrontation jeopardizes the carefully-laid peacetime network built over decades, which must be carefully regarded as great power competition in the Indo-Pacific continues to intensify.

For those that might decry this argument as alarmist or discounting years of partnership, consider the state of the U.S.-Philippines alliance. Linked by a Mutual Defense Treaty, the two states’ militaries have stood prepared to fight shoulder-to-shoulder for decades. In February of this year, Philippines President Rodrigo Duterte announced his intention to terminate the Visiting Forces Agreement that, in large part, undergirds that same alliance. The U.S. expectation of access, a key planning consideration, evaporated overnight.

Looking back three decades, we see the U.S. military evicted from its Philippine bases in Clark and Subic Bay in a similar vein. President Duterte has been vocal since his election regarding his intention to rebalance Philippines’ foreign relations, with the subtext being a move closer to China. It is easily posited that this decision is largely motivated by the expectation of economic benefit and uncritical security assistance. And this is coming from one of the supposedly closest U.S. allies in Southeast Asia.

What then of the defense partnership with Thailand, where the U.S. has long-relied upon the U-Tapao Royal Thai Navy Airfield to support combat operations, from Vietnam to Afghanistan? Thailand’s military is now led by openly pro-China officers and their branches have recently concluded a number of high-profile purchases of major weapons platforms from China. Should the U.S. and China enter into hostilities, would Thailand offer the use of its strategic airfield with the knowledge that it might be severing ties to the source of its own military equipment? This is, of course, only the military aspect. China is also Thailand’s largest trading partner.

If the depth of U.S investments and shared interests with its closest Southeast Asian allies are crumbling during peacetime, what then does this portend for access with less formally aligned states during open conflict with the PRC? In the face of mounting evidence to the contrary, should the U.S. government continue to rely on the prospect of unfettered access to logistical support and conduct offensive operations, as it has for the past 30 years? Or is it setting up the possibility of the Joint Force having to play a scratch game as its forward elements are ejected by non-belligerents at the outset of a conflict?

All Dressed Up with Nowhere to Go

Spanning from critical repair and replenishment functions to overflight permissions and divert airfields, the premise of access in nations such as Singapore, the Philippines, Thailand, Japan, Korea, and elsewhere is crucial to American operational plans. This loss will reduce the force generation capacity in theater, constrict avenues of approach, constrain operational flexibility, render the forward logistics chain brittle, and introduce friction into the crucial opening hours of a conflict as American forces potentially scramble to adjust to a new, unpracticed reality.

One of the first and most likely casualties to a restriction on access is the loss of crucial airfields. These airfields enable everything from air dominance operations and anti-submarine warfare, to battlefield awareness and transportation of personnel and material. While their loss does not mean that the United States and coalition partners will be unable to conduct air operations within the First Island Chain, both the number of sorties and on-station time will be significantly reduced as aircraft have to fly from more distant locales. This in turn will strain the U.S. aerial refueling capability, which will be hard pressed to sustain long range operations as well as facilitate reinforcement transfer to the theater. Further, it raises the specter of increased losses, as damaged aircraft or those without return tanker support will be without a proximate place to land. Finally, it will curtail the effectiveness of the forward arming and refueling points (FARPs), which are currently touted by the Joint Force as a way of conducting distributed and short duration aviation operations from non-fixed points.

Kadena Air Base, Japan (Apr. 1, 2015) – Twelve U.S. Air Force KC-135 Stratotankers from the 909th Air Refueling Squadron taxi onto the runway during the Forceful Tiger exercise. (U.S. Air Force photo by Staff Sgt. Marcus Morris)

Singapore offers a multi-faceted case study. Viewed by many as the Southeast Asian partner closest to the United States, Singapore hosts the U.S. Navy command responsible for organizing logistics operations across the U.S. Seventh Fleet, as well as the headquarters which controls U.S. Navy Littoral Combat Ships in the region. As a related aside, the U.S. military presence in Singapore began when Singapore offered its Sembawang facility to the U.S. Navy when it was evicted from its bases in the Philippines in 1993. U.S. ships today are rotationally deployed to Singapore’s Sembawang port facility, and the Changi Naval Base was expanded for the express purpose of accommodating U.S. nuclear-powered aircraft carriers. U.S. P-8A routinely fly from Singapore’s Paya Lebar Air Base.

However, Singapore’s Prime Minister has already warned the U.S. publicly that forcing a choice between supporting the U.S. or China would be “very painful,” pointing out that, notwithstanding Singapore’s partnership with the United States, its economy is far more reliant on China. Singapore prides itself on charting a balanced course between the two competing superpowers and in the event of a U.S.-China war, its preferred position would be neutrality. The port, airfield, and logistics support currently enjoyed by the United States would place Singapore’s domestic infrastructure at unacceptable risk during a major conflict with China. Unless Singapore’s interests were directly affected by this hypothetical war, it seems very likely that U.S. forces would politely be asked to relocate, and by a partner proximate to one of the most significant chokepoints in the region.

The USS Coronado at Changi Naval Base in Singapore on Oct. 16, 2016. (Roslan Rahman/AFP via Getty Images)

It is not too much of a stretch to imagine that non-belligerents, under PRC pressure and having curtailed access to their territory, might conceivably restrict permission to overfly their country as well. This would severely limit the avenues of approach of air power and reinforcements flowing into theater as they are forced to detour around the airspace of erstwhile partners. This in turn would allow the PRC to concentrate its forces – backed up by a mainland-based reconnaissance strike complex (see Figure 1) – on these narrow vectors, such as the Luzon and Singapore straits. While coalition aircraft could overfly this previously friendly territory, to do so might invite armed challenge in response to violations of the nation in question’s sovereignty. It also risks poisoning the narrative concerning the justification of the conflict.

Figure 1: China’s Regional Missile Threat (CSIS)

The issues attendant with the loss of access are further compounded by an insufficient amount of long-range munitions. While the United States plans to buy an additional 1,625 long range “missiles with ship-killing potential” between Fiscal Year 2020 and 2025, it has only acquired approximately 1,050 weapons since Fiscal Year 2011. Comprising the Long Range Anti-Ship Missile (LRASM), Standard Missile-6 (SM-6), and Maritime Strike Tomahawk (MST), the latter two weapons are multi-purpose, and consequently may be in high demand across a globe spanning force. When considered in the context of a dearth of available shipboard launchers, the potential loss of proximate locations for USMC expeditionary advanced bases, a lack of a robust mining capability, a fragile logistics chain, and an inability to conduct forward reloading of VLS, the reduced sortie rate induced by the loss of access becomes very problematic indeed. While the Defense Department is working to address many of the identified issues, they are still extant today, raising the specter of the United States being unable to achieve its stated goal of deterrence by denial.

Where Do We (Figuratively) Go From Here?

If we accept the premise that access to forward fighting positions may be curtailed in the event of a conflict with the People’s Republic of China for foreign political or diplomatic reasons, then the United States must make prompt investments to maintain credible deterrence. While the Pacific is primarily a maritime theater – indeed, as Bryan McGrath wrote, “if it is […] the desire of the United States not to be displaced, American seapower will have to shoulder a disproportionate share of the load” – the response will require investments across the Joint Force. While some of these investments are already being made, not all are being undertaken with sufficient alacrity or scale, and are likely to be high on the divestment list in the event of declining defense budgets. Many of these initiatives – from sealift recapitalization to additional defenses for Guam – have been talked about for years, during which little to no action was taken. If the United States is to maintain a credible deterrent posture vis-a-vis the PRC, investments must be made in this “priority theater” promptly and at scale. They will not only hedge against a loss of access, but may sufficiently reassure regional partners to ward off such an outcome.

The United States will have to examine the difficult prospect of violating the sovereignty of non-belligerents in a time of war. There may well come a point when the Joint Force will have to seize key positions along the South China Sea periphery – for example, in the Philippines, Indonesia, or Malaysia – for short durations in order to facilitate operations. These operations could conceivably span from landing covering forces for chokepoint transits, or establishment of sea denial positions, to replenishment of naval vessels in calm bays or setting up FARPs in austere locales. This introduces a number of issues, including raising the risk of severe reputational damage – possibly poisoning popular will against the U.S. war effort – and the prospect of the violated party’s forces challenging these temporary occupations with force. Preparing informal access arrangements, messaging narratives, and seizure CONOPs will be vital to achieving temporary operational access when it is otherwise denied. A unified joint Foreign Area Officer team will need to stand prepared to broker these agreements when the time comes.

Japan’s invasion of the Malayan peninsula in 1941 perfectly illustrates the consequence of the failure to prepare for this scenario. Britain, unwilling to violate Thai neutrality, allowed the Imperial Japanese Army to conduct a mostly-unmolested amphibious landing which would lead to the fall of Malaya 73 days later.


Hedging against the risk of an unexpected and unceremonious eviction from forward positions at the onset of major war is not something to be dismissed because it is an inconvenient scenario, nor does the response require particularly imaginative solutions. It requires the expansion of existing or in-development capabilities to a capacity capable of supporting large-scale expeditionary operations by the Joint Force. Indeed, there are many commonalities between what has been discussed, and the effects of a first strike on U.S. forward positions by the PLA’s Rocket and Air Forces, namely the loss of enabling shore-based infrastructure. The key difference is that the Joint Force will not be able to rely on surging temporary forces – ISR, logistics, strike, and others – onto alternate or austere sites on the territory of allies and partners in certain scenarios.

The U.S. must prepare, today, for the possibility of a zero access environment in a western Pacific contingency to preserve military options and avoid losing a conflict before the first shots are fired. Failure to prepare may leave the United States in a situation akin to that of Rear Admiral Dewey’s fleet in 1898 when they were forced to depart from neutral Hong Kong “without a home base or reliable source of coal in wartime,” essentially to conquer or die. This time, the away team won’t be facing a decrepit Spanish fleet, but the most formidable military challenger in a generation.

Blake Herzinger (@BDHerzinger) is a civilian Indo-Pacific defense policy specialist and U.S. Navy Reserve officer. The views expressed in this article are those of the author alone and do not represent those of his civilian employer, the U.S. Navy, the Department of Defense, or the U.S. government.

Elee Wakim (@EleeWakim) is a surface warfare officer in the U.S. Navy Reserve and a Presidential Management Fellow. The views expressed here are his own and do not represent those of the U.S. Navy, the Department of Defense, or the U.S. government.

Featured Image: Singapore (Jul. 14, 2015) – The littoral combat ship USS Fort Worth (LCS 3), top left, and the Arleigh Burke-class guided-missile destroyer USS Lassen (DDG 82), top middle, rest in port at Changi Naval Base during Cooperation Afloat Readiness and Training (CARAT) Singapore 2015. (U.S. Navy photo by Mass Communication Specialist 1st Class Jay C. Pugh/Released)

Let Me Get this Strait: The Turkish Straits Question Revisited

Chokepoints and Littorals Topic Week

By Paul Pryce

The Bosporus and Dardanelles Straits, together with the adjoining Marmara Sea, are known collectively as the Turkish Straits and provide the only access between the Black Sea and the Aegean Sea. More than 40,000 vessels passed through these waters in 2019, transporting almost 650 million tons of cargo, and reaffirming the Turkish Straits as one of the most important maritime trade corridors in the world. Additionally, the shores of the Straits – which narrow at some points to as little as 700 meters apart – are home to more than 22 million people, including the historic city of Istanbul.

Since 1936, the Montreux Convention Regarding the Regime of the Straits, hereinafter referred to as the Montreux Convention, has allowed for the peaceful flow of commerce through the Turkish Straits. However, recent calls from Turkish and Russian policy circles for revisions to the Montreux Convention should be cause for concern, as these proposals threaten to either spur a naval arms race in the Black Sea region or look to exploit the Straits as a geostrategic chokepoint.

The Montreux Convention

The Montreux Convention sought to address questions regarding the status of the Turkish Straits that, by the time of the Convention’s writing, had persisted for well over a century, occasionally culminating in violence or near-violence, as in Britain’s effort to wrest control of the Dardanelles in 1922. Among its terms, the Convention stipulates that only littoral states to the Black Sea may transit capital ships (which, if we follow the 1923 Washington Naval Treaty’s definition, refers to “…a vessel of war… whose displacement exceeds 10,000 tons… or which carries a gun with a caliber exceeding 8 inches…”) through the Straits, escorted by no more than two destroyers.

The Bosporus Straits, straddled by Istanbul, are the gateway to and from the Black Sea. (Image: Marine Vessel Traffic)

It also prohibits any country from deploying to the Black Sea more than nine naval vessels displacing a total aggregate of 45,000 tons; it requires that no group of non-littoral states deploy to the Black Sea any naval vessel weighing more than 10,000 tons; and it limits the stay of any vessels from non-littoral states to just 21 days. Littoral states are further obliged under the Convention to inform the relevant Turkish authorities of an intended transit of the Straits by a military vessel at least eight days prior and non-littoral states are obliged to provide 15 days’ notice. Turkey is further empowered to close the Straits to all military traffic in wartime or when under threat of aggression while also denying passage to merchant vessels belonging to countries at war with Turkey.

It is worth noting that Annex II of the Convention specifically excludes aircraft carriers from the definition of a capital ship. This does not extend to any other ship transporting aircraft since, at the time of the Convention’s writing, it was not uncommon for battleships and other military vessels to carry observation aircraft. This may explain the Soviet Union’s unusual designation of its aircraft carriers as ‘aircraft-carrying cruisers’ – for example, the Kiev and Kuznetsov classes. These vessels could fulfill the same strategic function as carriers while still being free to transit the Turkish Straits, even as the Convention denied access to the Black Sea for NATO aircraft carriers due to their explicit designation as aircraft carriers in both name and function.

Though the Montreux Convention has constrained the capacity of NATO support to Ukraine in its struggle against Russian aggression, such as by limiting the number of vessels permitted in the Black Sea as part of Standing NATO Maritime Group 2 (SNMG2), the continued implementation of the agreement is in the national interest of the United States and other non-littoral nations. The United States has long supported the “principle of freedom of transit and navigation” referred to in Article 1 of the Convention and, although it has never ratified the United Nations Convention on the Law of the Sea (UNCLOS), the United States already abides by UNCLOS as a matter of customary international law.

On the one hand, this seems to suggest that challenging the legitimacy of the Montreux Convention would advance American interests – after all, the International Court of Justice (ICJ) ruled in 1949 that, for vessels transiting the Straits or Corfu, which runs along the coasts of Albania and Greece and which serves as a passage between the Adriatic and Ionian Seas, the concept of innocent passage should prevail over any claims of state control over such strategic waterways. With the Corfu precedent and the customary nature of UNCLOS, one might assume that a legal challenge of the Montreux Convention by a non-littoral state would easily succeed.

But the unique geography of the Turkish Straits makes this legal question far from simple. The Marmara Sea is an internal sea, all the coasts of which belong to Turkey. In the event of a dissolution of the Convention, the ICJ would need to consider whether the Turkish Straits constitute a single strait connecting two open seas, in which case innocent passage prevails, or if they are two separate straits connecting an open sea and an internal sea, in which case Turkey would be able to exert even greater control over the flow of maritime traffic through the Straits. Referring to the Turkish Straits in common parlance – rather than referring separately to the Dardanelles, the Bosporus, and the Marmara Sea – implies a single unit, and the bulk of the maritime traffic has flowed over the past decade between the Aegean Sea and the Black Sea. It would seem likely then that the ICJ would favor the conception of the Turkish Straits as a single strait connecting two open seas, but this outcome is not guaranteed.

The Turkish Straits are comprised of: (A) The Dardanelles, (B) The Marmara Sea, and (C) The Bosporus. (Image: Maritime Studies South Africa)

It is also difficult to discern to what extent the United States would be able to practically alter the administration of the Turkish Straits. Turkey is a significant maritime power in its own right and much of its naval forces are stationed at Gölcük Naval Base, located on the east coast of the Marmara Sea. Any freedom of navigation operation (FONOP) would encounter immediate resistance and would add to the existing tensions between the Turkish and U.S. governments, especially as Turkey refuses to recognize UNCLOS.

The economic and social importance of the Straits to Turkey cannot be overstated. Beyond the millions of Turkish citizens who live on its banks and the commerce the Straits facilitate, it also offers a physical representation of Turkey’s duality as a European and Asian state, while the administration of the Straits has afforded Turkey a self-image as the guardian of the Black Sea.

Given all of this, it would possibly require the wholesale destruction of Turkish naval forces to impose a major change in the administration of the Turkish Straits and, even then, barriers could be erected intentionally or accidentally that would interfere with the future use of the waterway. In short, the legal and practical status quo offers the best guarantee for the continued flow of trade through the Straits.

Calls for Reform

However, there has been much discussion in Russian and Turkish policy circles around possible revisions to the Montreux Convention. These revisions would be detrimental to U.S. national interests, which include the maximum possible freedom of transit and navigation through the Turkish Straits. In particular, since the annexation of Crimea, some Russian defense planners have called for the Convention to be revised so that the length of stay in the Black Sea for vessels from non-littoral states would be shorter than the current allowance of 21 days. Furthermore, Russian policymakers have creatively interpreted the Convention since annexing Crimea in 2014.

In May 2016, Turkish President Recep Erdogan decried the Black Sea as a “Russian Lake.” In response, the Chair of the State Duma Committee on Defense, Admiral Vladimir Komoyedov, claimed that the Russian Federation need only inform Turkey of the transit of its military vessels through the Turkish Straits and that restrictions on the number and kind of vessels transiting applied only to non-littoral states. Meanwhile, in response to Russia’s unilateral restrictions on the flow of maritime traffic through the Kerch Strait between the Black Sea and the Sea of Azov, Ukraine called in November 2018 for tighter restrictions on the number and kind of vessels from all states transiting the Turkish Straits, in hopes that this might interfere with the strategic maneuvers of the Russian Navy.

Russian Navy warships based in the Black Sea (Wikimedia Commons)

There have been rumblings from the Turkish government as to how Istanbul is “…threatened by the ever growing number of oil tankers and other dangerous cargo vessels” that transit the Straits. While Turkey has been mostly satisfied by regulations adopted through the International Maritime Organization (IMO) and other multilateral bodies, some Turkish commentators have proposed further action. In particular, some suggest promoting a regional ownership model for the Straits under the auspices of the Black Sea Economic Cooperation (BSEC), a multilateral forum comprised of Turkey and the Russian Federation but also Albania, Armenia, Azerbaijan, Bulgaria, Georgia, Greece, Moldova, Romania, Serbia, and Ukraine.

Such a model could facilitate the re-interpretation of the Montreux Convention, loosening the restrictions on vessels from Black Sea littoral states, but maintaining or even tightening the restrictions on vessels from non-littoral states. This could, in turn, be circumvented by the United States and other non-littoral states by re-flagging vessels. In the wake of the Crimean annexation, some American commentators suggested an enhanced NATO presence in the Black Sea by having U.S. Navy ships fly Bulgarian or Romanian flags. But this, too, would likely only add to tensions between the United States and Turkey as well as further undermine the rules-based order.

The Istanbul Canal

A $25-billion infrastructure project announced in 2011 by Turkey’s then-Prime Minister Recep Erdogan, known as the Istanbul Canal, presents the greatest challenge to the legal and practical status quo in the Turkish Straits. The canal would consist of a 45-kilometer waterway bisecting the European side of Istanbul, allowing 160 vessels daily to bypass the Bosporus as they transit between the Marmara and Black Seas. Officially, the Istanbul Canal was proposed to alleviate congestion on the Bosporus and divert tanker traffic toward less sensitive areas of Istanbul. However, Turkish freighter captains have cast doubt on this, noting that the canal as currently envisioned would be too shallow to accommodate many of the tankers Erdogan claims would be diverted from the Bosporus. Indeed, the canal plan calls for a maximum draft of 17 meters.

In reality, the Istanbul Canal may have been introduced to circumvent the Montreux Convention. In January 2018, Turkey’s then-Prime Minister Binali Yıldırım asserted that, as an artificial waterway, the Convention would not apply to the Istanbul Canal and so the Turkish authorities would be able to unilaterally restrict or regulate traffic through it. This again depends on whether the Turkish Straits are understood to be a single unit or as three distinct waterways – the Dardanelles, Marmara, and Bosporus. In the former interpretation, the Convention could still apply to the canal, given that it connects part of the Straits to the open waters of the Black Sea. In the latter interpretation, however, the canal would be an entirely new and distinct feature to which the Convention would indeed not apply.

Project route of the Istanbul Canal. (Image: TRTWorld)

In any case, the canal presents a serious threat to the spirit of the Convention. On the one hand, Turkey has consistently advanced the narrative that continued use of the Bosporus is unsafe to the natural environment, the millions who live on its banks, and the hundreds of vessels that transit each day, and so unilateral restrictions on maritime traffic through the Bosporus could be justified on the basis that vessels ought to transit the safer canal route. On the other hand, Turkey could upset the balance of power in the Black Sea region by allowing vessels to transit the canal that would have otherwise been denied passage through the Turkish Straits under the Convention. Either scenario would clash with the U.S. policy of seeking the maximum possible freedom of transit and navigation, while also making NATO’s capacity to support members and partners in the Black Sea region contingent on Turkish whims.

Similar concerns regarding Erdogan’s strategic intentions have been expressed in Russia, with some commentators warning that completion of the canal could soon be followed by a Turkish denouncement of the Montreux Convention. Under the Convention’s provisions, a denunciation by any of the signatories would prompt a conference to be held for the purposes of drafting amendments to the existing Convention or an entirely new agreement on the use of the Turkish Straits. For such a conference to be valid, the Convention calls for participation from three-quarters of the “High Contracting Parties” that are littoral states – in other words, five out of six of what is now Ukraine, Romania, Bulgaria, Georgia, Russia, and Turkey.

It is conceivable, then, that a denunciation by Turkey of the Montreux Convention could be followed by a conference to draft a new agreement, held validly without Turkish participation. But it is unlikely Turkey would readily abide by any new agreement that was drafted without its participation, especially when, from the perspective of the Turkish authorities, the Istanbul Canal and the denunciation of the Montreux Convention would afford Turkey full control over access between the Aegean and the Black Seas.

Open Channels

Fortunately, there are diplomatic options available that could preserve the status quo in the Turkish Straits. For example, through the auspices of the Organization for Security and Cooperation in Europe (OSCE) – of which the United States and all the Black Sea littoral states are members – a series of confidence- and security-building mechanisms (CSBMs) could be developed regarding access between the Aegean and the Black Sea. As exemplified by the Vienna Document, an integral document to the work of the OSCE, CSBMs can include annual exchanges of information on the disposition of military forces, base inspections, and the mutual invitation of observers to military exercises, all of which are intended to demonstrate to neighbors that there is no hostile intent behind various military activities in border areas.

The development of a similar document or agreement pertaining to the Turkish Straits could include a commitment from all parties not to interfere in any way with access between the Aegean and the Black Sea, aside from those powers already afforded Turkey under the Montreux Convention, effectively backstopping the Convention but also de facto extending its remit to any artificial waterways that might be established connecting the Aegean and Black Seas.

There is nothing here that would stop Turkey from refusing to abide by these terms at some later date – after all, Russia suspended its participation in the Conventional Forces in Europe (CFE) Treaty, another OSCE-related CSBM, a little over one year before it mounted its 2008 attack on Georgia. But a suspension of Turkish participation in CSBMs related to the Straits would afford an early warning to the U.S., Russia, and other interested parties that a denunciation of the Montreux Convention may be forthcoming.

Even with a Turkish denunciation of the Convention, CSBMs would help to avoid a regional arms race. The continued exchange of information between the other Black Sea littoral states would provide assurance that no one state intends to take advantage of the change in the practical and legal status of the Turkish Straits, such as by securing a side agreement with Turkey that would allow for an increased buildup of naval forces in the Black Sea. The inclusion of some clear punitive measures for state non-compliance in the CSBM could also deter Turkey from unilaterally altering the practical or legal status of the Straits – for example, the imposition of sanctions by all other parties – but this could also make the conclusion of any agreement on the CSBM unlikely. In any case, it would serve Turkey’s national interests to participate in such an arrangement as CSBMs would provide a safety net for all of the concerned parties, helping to avoid any change in the legal or practical status of the Turkish Straits from escalating into armed conflict.

Beyond multilateral agreements and fora, Erdogan must also contend with public opinion at home. The newly elected Mayor of Istanbul, Ekrem İmamoğlu, has expressed strong opposition to the Istanbul Canal project and handily defeated former Prime Minister Binali Yıldırım, a canal proponent and Erdogan ally, despite alleged efforts by the Turkish authorities to skew the election results in Yıldırım’s favor. Calls for a referendum on the canal also bode ill for Erdogan, with polling in December 2019 showing that more than 72 percent of Istanbul residents are opposed to the project. The canal could be sacrificed in hopes of avoiding a showdown with İmamoğlu for the presidency in Turkey’s anticipated 2023 general election.


Given the strategic importance of the Turkish Straits – and the rumblings for reform from Ankara, Moscow, and even Kyiv – the most prudent course for U.S. policymakers would be to ensure open diplomatic channels, both by pursuing commitments from littoral states in multilateral fora like the OSCE, and by maintaining an open dialogue with all Turkish stakeholders on this issue. Neglecting these diplomatic tools would mean surrendering the initiative to the Turkish authorities, who have thus far demonstrated a willingness to erode the legal order that has governed the Turkish Straits for nearly a century whenever it is deemed to serve narrowly defined national interests.

Paul Pryce is the Principal Advisor to the Consul General of Japan in Calgary, and a long-time contributor to the Center for International Maritime Security (CIMSEC). He has previously written as the Senior Research Fellow for the Atlantic Council of Canada’s Maritime Nation Program and earlier served as a Research Fellow with the Organization for Security and Cooperation in Europe (OSCE) Parliamentary Assembly.

Featured Image: Turkish Navy MILGEM corvette transits by the Dur Yolcu Memorial on its way to the Dardanelles (Turkish Ministry of Defense photo)