Goodbye Grotius, Hello Putin

Sunday’s encounter between Russian and Ukrainian vessels in the Kerch Strait, the entryway to the Sea of Azov east of the Crimean peninsula, revived an age-old question in international politics: Can a coastal nation own the sea? International law says no; authoritarian states such as China and Russia say yes. Which view prevails may depend on whether seafaring societies band together and push back effectively against Moscow and Beijing.

Russian ships detained two Ukrainian gunboats and a tugboat after an exchange of fire and after deliberately ramming the tugboat. As of this writing, a Russian judge has ordered 12 of the 24 captured Ukrainian mariners to be held until trial in late January. It was the culmination of an increasingly provocative Russian policy.

In recent months, Moscow has taken to treating the Kerch Strait as a border checkpoint—a point of entry to sovereign Russian territory. Guards demand that Ukrainian ships request permission before transiting the strait; Ukraine rejects Russia’s right to regulate passage through the sole gateway to Ukraine’s southeasterly seacoast.

Moscow has upped the stakes because it can. Russia annexed Crimea in 2014, granting Russian border guards physical control of both sides of the strait. The new policy flouts a 2003 bilateral agreement designating the Kerch Strait and Sea of Azov “historically internal waters of the Russian Federation and the Ukraine.” The pact guarantees ships flying the flags of both countries “free navigation” through these seaways. The two governments further pledged to negotiate a boundary between waters they control. They never did.

Analyses of the recent conflict at sea make much of how it relates to the shadowy land war in eastern Ukraine. Barricading the Kerch Strait makes the Sea of Azov a Russian lake; the Russian Navy can use the sea while the Ukrainian Naval Forces cannot. In other words, Russia’s navy now has the luxury of projecting power ashore or running in supplies from that safe haven while barring its foe from doing the same—a time-honored strategy of stronger naval powers. The U.S.-led coalition made short work of Saddam Hussein’s navy in 1991. Sinking most of the Iraqi fleet and bottling up the remnants in port allowed the coalition to bring in supplies in bulk by sea and pummel Iraqi targets with missile and airstrikes from offshore. (I know; I helped sink the Iraqi Navy.)

This is a maritime flanking movement of considerable import for both combatants. Ukraine finds itself geographically and diplomatically isolated—the best of all worlds for a big power intent on bullying a smaller one. Might now makes right in the Sea of Azov. And might favors Russia lopsidedly.

But Moscow may have more ambitious goals. Indeed, imposing control of the strait helps Russian President Vladimir Putin and his government chip away at the U.S.-led legal order of the seas, much as President Xi Jinping’s China has eroded navigational freedoms in the South China Sea. Both Beijing and Moscow covet the right and power to dictate what happens in offshore waters. They have resorted to armed force to buttress their extralegal claims and are counting on competitors to be unable or unwilling to contest those claims effectively.

China manufactures, arms, and fortifies artificial islands to uphold its maritime claims. Russia is leveraging its control of a vital strait. Given time and sufficient physical strength, the Chinese-Russian entente may rewrite the rules governing seaborne endeavors in both Southeast Asia and the Black Sea basin. They could forbid surveillance flights, naval flight operations, underwater surveys, and a host of other activities permitted under the law of the sea. That would leave Western forces unfamiliar with potential battlegrounds—and thus at a marked disadvantage in future conflicts.

Take the South China Sea. China’s People’s Liberation Army (PLA) has erected what U.S. Pacific Command boss Adm. Phil Davidson terms a “Great Wall of SAMs,” referring to the surface-to-air missiles now deployed on islands and atolls dotting the sea. Russia can do China one better. The South China Sea is a vast expanse where many coastal and seagoing states have a stake in maritime freedom. The Sea of Azov, by contrast, is a compact theater cut off geographically from the larger Black Sea. It’s also a theater where both parties to the quarrel agree they’re the only two stakeholders.

Geography, physical might, and diplomacy render it virtually impossible for NATO and other outsiders to intercede on Kiev’s behalf. Unlike the broader Black Sea—where NATO members, namely Turkey, are players and potential opponents for Russia and where access for all navies through the Bosporus and Dardanelles straits is regulated by the 1936 Montreux Convention—there is no such regime for the Sea of Azov, an inland sea of the Black Sea.

Over the longer term, Russia can hope to browbeat Ukraine into acceding to its de facto sovereignty over the Sea of Azov, just as China has evidently cowed the Philippines (and is attempting to cow Vietnam and other maritime claimants) into tacitly accepting its possession of reefs and atolls such as Scarborough Shoal and Mischief Reef. China’s navy and coast guard ensconce themselves on islands and atolls and dare outmatched opponents to dislodge them. This is happening despite a 2016 international court ruling pronouncing China’s seizure of features within the Philippine “exclusive economic zone” unlawful.

A view of the bridge across the Kerch Strait on Nov. 25 after Russia blocked access to the Sea of Azov. (Alexei Pavlishak/TASS via Getty Images)

Under the traditional understanding of maritime law, as codified in the 1982 U.N. Convention on the Law of the Sea, sovereignty applies only to dry land and to a 12-nautical-mile “territorial sea,” or strip of sea immediately offshore. Neither China nor Russia appears to accept that landbound doctrine. The two countries seem to think they can redefine water as national territory.

If they get their way, lawmakers in Beijing and Moscow will make the rules stipulating what navies and merchant fleets may do there. They will restrict military activities in particular. Beijing aspires to enforce “indisputable sovereignty” within a “nine-dash line” it has sketched on the map enclosing most of the South China Sea. Beijing based its claims to nautical sovereignty on the notion that Chinese seafarers have made use of South China Sea’s waters since time immemorial. (The U.N. convention expressly forbids such historical claims.) Moscow is attempting something similar within the solid rim that encases the Sea of Azov.

If strong coastal states make unlawful claims and no one reverses them, they could redefine freedom of the sea out of existence—and repeal the law of the sea in areas where they brandish superior military might.

These controversies are the latest round in a very old—and, we thought, settled—argument over freedom of the sea. Back in the 17th century, the father of international law, the Dutchman Hugo Grotius, and the English jurist John Selden debated whether coastal states could own the sea. Grotius said no, Selden an emphatic yes.

Grotius published a treatise titled Mare Liberum in 1609 arguing that the sea is no one’s property. It is a mostly ungoverned expanse that belongs to everyone and no one. No coastal state acts as lawgiver. Not so, insisted Selden. The English scholar issued a belated rejoinder in 1635 with Mare Clausum, insisting that the English crown was sovereign over the seas lapping against the British Isles. Geographic position coupled with naval power entitled London to control the approaches to northwestern Europe—including Grotius’s Netherlands.

In Selden’s view, English rulers made the laws governing merchant and naval shipping, and fellow European rulers were bound to obey. Under Selden’s doctrine of the closed sea, oceans and seas belonged to whichever sovereign boasted a navy strong enough to crush rival claimants.

Until recently, Grotius appeared to have won out. The framers of the U.N. convention codified his idea of the open sea, sharply circumscribing coastal states’ authority beyond their territorial seas. But Russia and China seem bent on gradually—almost imperceptibly—resuscitating the closed-sea doctrine. The slow pace of change makes it hard for allies to summon the sense of urgency that propels multinational undertakings. If Moscow and Beijing succeed in the Sea of Azov and South China Sea, they will have abridged the legal order premised on free use of the sea. And they will damage the United States’ geopolitical standing in the process.

During World War II, the Yale geopolitical scholar Nicholas Spykman pointed out that Great Britain could assemble and rule a liberal maritime empire because its Royal Navy commanded the “marginal seas” abutting the Eurasian periphery. In other words, British seafarers, soldiers, and diplomats enjoyed ready access to the continental landmass from the Baltic Sea, Persian Gulf, South China Sea, and other peripheral seas. They could radiate power inland at will to advance British interests.

While the United States doesn’t rule an empire per se, it has no strategic position in the coastal regions of Western Europe, East Asia, or South Asia without guaranteed access to allies in the marginal seas. Take away access to bases in Italy, Japan, or Bahrain and the U.S. Navy and fellow armed services must fall back. Spykman’s logic thus holds in this post-imperial world. In the end, the Black Sea and South China Sea disputes aren’t just about the legal order; they’re about geopolitical power and influence. If aggressors get their way in local disputes, they will stage further challenges in hopes of winning a seismic victory over time.

As Russia and China seek to extend their legal jurisdiction and military control, engineering works have become a major weapon in their arsenals. PLA engineers built Mischief Reef from a mostly submerged atoll into a military installation by 1998, while the United States and its allies were embroiled in Balkan wars and other controversies and paying little attention to Southeast Asia. That set a bad precedent. Beijing followed up starting in 2013—giving rise to today’s network of island fortresses that threaten any navy or coast guard that cares to oppose Chinese claims to sovereignty. That applies not just to the U.S. Navy and Southeast Asian navies and coast guards but to the Royal Australian Navy and Indian Navy, as well.

For their part, Russian engineers constructed a bridge spanning the Kerch Strait after Russia annexed Crimea. Visually speaking, the bridge completes the southern rim of the Sea of Azov. But it constitutes a barrier to nautical movement in more than a metaphorical sense. The main span of the Kerch bridge is just 108 feet high, capping the height and thus the size and capacity of merchant and military vessels that can pass beneath. A public infrastructure project has, in effect, disrupted Ukraine’s logistics and constrained its combat power off its own coast.

Russian President Vladimir Putin inspects the road section of the bridge over the Kerch Strait on March 14. (Yuri Kochetkov/AFP/Getty Images)

In October 1939, British Prime Minister Winston Churchill depicted Russia as a “riddle wrapped in a mystery inside an enigma.” It remains so. But in that BBC broadcast, Churchill hastened to add: “perhaps there is a key. That key is Russian national interest.”

The national interest in Putin’s eyes is regaining control of geographic space adjoining Russian frontiers. Moscow considers maritime space part of the effort. And its interest in seaborne affairs is nothing new. In 1988, for instance, the Soviet Navy dispatched a vessel to deliberately—albeit delicately—collide with a U.S. Navy cruiser passing within Soviet territorial waters in the Black Sea. The “Black Sea bumping incident” expressed Soviet leaders’ displeasure with Western naval operations too close to home.

As Churchill prophesied, Moscow has pursued strategic interests with admirable consistency. Yet it dependably deploys unpredictable methods and tactics to advance its strategic quest. Indeed, the Kremlin has dusted off its Cold War playbook. Soviet strategy sought to layer these offshore waters and the skies above into a “blue belt of defense,” or buffer zone against Western naval operations. A latter-day blue belt is in the offing.

To combat Russia’s low-level aggression, the United States and its allies must first admit they have a problem. Freedom of the sea is indivisible. If Russia makes itself the de facto sovereign of the Sea of Azov, future moves in its incremental strategy will soon follow. Its strategy will imperil the broader Black Sea and eventually the eastern Mediterranean Sea and the Baltic Sea.

Second, fashion a Hippocratic strategy: Do no harm. Reversing Russian gains in the Sea of Azov may prove impractical for the United States and its allies. But Western diplomats must do nothing to abet Russian strategy. At the same time, they must go out of their way, early and often, to state that no coastal state may modify the law of the sea by fiat. It will be far easier for the West to contest the wider Black Sea and other peripheral waters than the Sea of Azov. If and when Moscow overplays its hand, Washington should rally fellow seafaring states to oppose Russian encroachment. Such Russian overreach could translate into Western advantage.

Finally, the U.S. government must devise a strategy and develop the military tools to restore American mastery of the marginal seas. Force ultimately underwrites the international legal order, including its saltwater component. Russia and China have deftly integrated shore-based weaponry—anti-ship and anti-air missiles, fast patrol craft and submarines, and the like—into their maritime defenses. Their goal is to make things tough for the U.S. Navy, which presides over freedom of the sea, should the American fleet ever venture into their environs.

The logic of “anti-access” cuts both ways, however. The United States and allied militaries should harness it, fielding access-denial forces and strategies of their own to make things just as tough on Russia and China. Seashores and coastal waters bristling with armaments are hardly a desirable solution. But it’s the best of a bad lot. A feeble response would endanger a system that serves the seagoing world well.

Washington must push back hard.