Editor's Note: The author has written an accompanying piece, "Why We Defend Free Seas," to explain what is at stake in the conflict in the South China Sea that this essay describes.

The present U.S. approach to countering incremental Chinese aggression in the South China Sea has failed. U.S. Navy freedom of navigation operations (FONOPs) are not achieving their long-term political-diplomatic objectives of upholding the rule of international law or substantively changing China’s belligerently revisionist attitudes and behavior in the region. But while the cancerous expansion of China’s fortified outposts and coercive maritime presence in the South China Sea is more advanced than when U.S. FONOPs began, there still is time to salvage the situation before key actors either politically recognize China’s ill-gotten gains or capitulate to its continental conception of sovereignty over distant ocean areas.

This is not the first time the United States has seen this kind of subversive menace, and the U.S. Sea Services need only look to their history to derive insights from bluejackets and Marines who employed innovative, forward-leaning strategies to overcome similar challenges. Staging a recovery starts by coming to a new understanding of the core nature of the threat, reexamining current efforts to determine their effects on the decisive centers of gravity, and applying learning from the not-too-distant past to craft new strategies and operational concepts. Together, these efforts will capture the initiative and achieve the just aim of upholding the freedom of the sea and the rule of law.

The Strategic Problem

For nearly four centuries, customary (and eventually formal) international law has treated the oceans as a global commons over which national sovereignty is limited and based strictly on adjacent landward holdings.1 Being dependent on overseas transportation for both economic and military access to most of the world’s population, the United States has long viewed this legal and philosophical principle—“the freedom of the sea”—as a fundamental national interest. Since 1945, the freedom of the sea has been an essential tenet of the U.S.-led rules-based liberal international order and has been profoundly beneficial for humanity—making possible unencumbered transoceanic exchanges that have driven global prosperity and lifted more people out of poverty and oppression than in any other era in history.2

Yet the underpinnings of this vital international legal regime are under grave threat in the South China Sea. China, despite being a party to the U.N. Convention on the Law of the Sea (UNCLOS)—and one of the chief beneficiaries of the post–World War II open maritime order—is advancing a revisionist, terrestrial view of maritime sovereignty, in which distant ocean areas can be claimed as if they were land as “blue national soil” to keep out other countries’ ships and mariners.3 Its actions run contrary to the accepted jurisprudence of UNCLOS and the Permanent Court of Arbitration’s (PCA) 2016 ruling in Philippines v. China, which largely divides the South China Sea among the exclusive economic zones (EEZs) of its bordering states and a narrow sliver of international water running through the rock and shoal-strewn “Dangerous Ground.”4 Rather than “the free sea,” China’s leaders apparently have embraced the concept of “the closed sea,” claiming “indisputable sovereignty” over the nine-tenths of the South China Sea that falls within Beijing’s self-proclaimed Nine-Dash Line, despite its invalidation by the PCA.5

And China has sought to make its legal statements a reality. Over the past two decades, China has tried to physically impose its own domestic law and alternative conception of maritime sovereignty on the unarmed civilians of its neighbors. Beyond China’s well-publicized fortification of maritime features and ongoing naval modernization and buildup, Chinese harassment of Southeast Asian maritime populations—in international waters and other states’ EEZs—in the South China Sea has become an almost unremarkable occurrence. The China Coast Guard and the People’s Armed Forces Maritime Militia routinely menace other countries’ fishermen—boarding or ramming boats, confiscating or stealing catch and equipment, and even going so far as to kidnap crewmembers for ransom.6 China unilaterally imposes seasonal fishing bans across wide swaths of the South China Sea under penalty of severe fines, detention, and vessel seizure.7 The depredations extend to other maritime resource-extraction activities as well. In 2017 and 2018, China threatened to attack Vietnamese positions in the Spratly Islands unless planned oil exploration projects within Vietnam’s EEZ were canceled—with the Vietnamese government submitting on both occasions.8

China’s Maritime Insurgency

Viewed as a whole, China’s actions constitute a campaign to undermine and ultimately overturn the prevailing regime of international law that governs the conduct of maritime activity in the South China Sea. The key dynamic at work is a “battle of legal regimes,” a political contest of wills that manifests itself in a duel between two competing systems of authority—the U.S.-underwritten system of the free sea, versus the Chinese vision of a closed, Sinocentric, and unfree sea.

Political will is manifested through law; in practice, then, the political contest is a struggle over whose law and authority are in force—those of the prevailing regime or those of a rival alternative regime. This requires that a law be accepted and, more important, adhered to by those it seeks to govern. In this sense, the actions of civilians in response to belligerents, as opposed to the actions of belligerents directed against each other, ultimately will decide the victor. As such, the decisive question in the ongoing battle of legal regimes in the South China Sea is not, Which side would prevail in battle? but rather, Whose laws do the civilians follow?

China’s pattern of action has a name: insurgency. Insurgencies are fought precisely to determine who governs, which makes the issue of whose laws the civilians follow the conflict’s overriding mechanism. As China has evidently recognized, for all the repetitions of the ubiquitous phrase “winning hearts and minds,” insurgencies are exercises in J. C. Wylie’s theory of power control.9 Civilians who lack defense against harassment or reprisal for exercising their rights under one regime have little choice but to submit to its opponent—even if their true preference or long-term material self-interest lies with the previous incumbent.

China’s maritime insurgency has proceeded thus far unimpeded because its higher-profile activities—its territorial seizures and expansion of antiaccess/area-denial envelopes—have so thoroughly captured U.S. and allied attention that they have obfuscated the decisive line of effort: the forcible coercion of civilian maritime populations.

China has been aided by the United States’ principal response, FONOPs. While transits within 12 nautical miles of occupied maritime features offer value as symbolic political and legal messages about nonrecognition of particular territorial claims, such operations are strategically inconsequential because they do not affect civilians’ confidence in their own ability to exercise their international legal rights. Both the civilians and the Chinese know that U.S. FONOPs are transitory gestures. As Chinese propagandists remind the world, the Americans always sail away, and civilians will be subject to intimidation and harassment as soon as the U.S. Navy is once again beyond the horizon.

Left unchecked, the eventual strategic outcome of China’s maritime insurgency will be to overthrow the prevailing system of international law at sea, impose an alternate, Chinese system of governance, and secure for China recognized de jure sovereignty over the vast expanse within the Nine-Dash Line.

Designing a Maritime Counterinsurgency

If the strategic problem in the South China Sea is a Chinese insurgency, it logically follows that the U.S. and allied strategic solution should be counterinsurgency. A maritime counterinsurgency strategy would seek to uphold the rule of international law by protecting local civilian mariners. In providing reliable physical protection against Chinese harassment, the United States and its allies would reassure civilian populations that the rules have not, in fact, changed, thus giving civilians the security and essential confidence to defy Chinese intimidation and exercise their lawful rights.

This is easier said than done, because the situation in the South China Sea is subject to several complicating factors. First and foremost is the conflict’s sub-kinetic, gray zone character—what Chinese sources refer to as “war without gun smoke.”10 Under current assumptions—that a shooting war would be costly and undesirable for all belligerents and that the United States will not initiate hostilities—U.S. and allied forces will have to achieve their objectives without fighting. This will constrain their ability to compel Chinese forces to stop coercing civilians. In addition, given China’s geographical proximity to the region, a U.S. maritime counterinsurgency campaign necessarily would operate under local military inferiority, which poses challenges for operations short of war and would be especially dangerous should the situation escalate.

This is where history plays an essential role, for U.S. forces have faced these conditions before and achieved their objectives by developing and implementing innovative strategies that can inform responses to today’s challenges.

The Interwar U.S. Asiatic Fleet

A compelling example of successful gray zone deterrence from a position of local military disadvantage can be found in the experience of the U.S. Navy’s small but experienced Asiatic Fleet on the China coast between 1937 and 1940. In the midst of Imperial Japan’s invasion of China, the 39 warships and 5,000 sailors of the Asiatic Fleet were confronted by a Japanese gray zone campaign aimed at forcing U.S. and Western interests out of China while avoiding open war with the Western powers. Japanese moves against the West during this period bear striking resemblance to those of China today, including blockades of key foreign outposts, attempts to infringe on free navigation on recognized international waterways, and the harassment (and at times, open attack) of foreign warships.11

Under the command of seasoned sailor-diplomat and longtime Asia specialist Admiral Harry E. Yarnell, the U.S. Asiatic Fleet adopted the policy that U.S. “naval vessels . . . will go wherever it is necessary at any time . . . and will remain in such places as long as American citizens are in need of protection or assistance”—an earlier era’s equivalent to today’s mantra that “the United States will fly, sail, and operate wherever international law allows.”12 Yarnell’s strategy for gray zone deterrence stressed continual military-to-military communication to assert U.S. legal rights and challenge Japanese infringements on the spot; the deployment of U.S. forces to maintain persistent physical forward presence at the point of gray zone attack; and the inculcation of a culture of independent judgment and mission command down to junior levels of responsibility. This approach allowed the Asiatic Fleet to punch above its weight by leveraging all its assets, from its commander’s diplomatically significant four-star rank, to the adaptive thinking and independence of its junior officers.

Admiral Harry Yarnell commanded the Asiatic Fleet from October 1936 to July 1939. Yarnell’s flagship, the USS Augusta (CA-31), is shown at anchor in Shanghai as the battle for the city rages on land in August 1937. Yarnell and his sailors carefully chose when, where, and how to confront Japanese forces to prevent escalation and avoid capitulation. Naval History and Heritage Command

Despite being materially outmatched by the Japanese battlefleet—based only a few hours’ steaming from China—the Asiatic Fleet successfully deterred the Japanese from taking overtly aggressive steps against U.S. interests. Its gray zone deterrence campaign ended only when deterioration in the global strategic situation led Yarnell’s successor, Admiral Thomas C. Hart, to withdraw the Asiatic Fleet to the Philippines in late 1940.

USMC Combined Action vs. the Viet Cong

There are significant parallels between Beijing’s efforts in the South China Sea and the Viet Cong’s activities against rural civilian populations in South Vietnam. Starting in 1959, the Viet Cong initiated a wave of nationwide violence to terrorize and coerce the population to comply with its own rule and noncompliance with the South Vietnamese regime. By targeting and eliminating local government officials, the Viet Cong isolated villages from the central government in Saigon. It positioned itself as the sole governing authority over rural populations, compelling civilians to recognize its rule through measures such as conscription and rice taxation, imposed by threats and acts of violence.13

On their arrival in 1965, the Marines responded with the Combined Action Program, which attached rifle squads of 15 U.S. Marines to platoons of roughly 30 South Vietnamese Popular Forces home-defense militia to create “Combined Action Platoons” (CAPs). Unlike the large-unit “search-and-destroy” sweeps favored by Army General William Westmoreland, CAPs lived and patrolled in individual villages and hamlets full-time to create long-term security and degrade the insurgents’ ability to exert coercive control. This gave the CAPs “credible permanence” in the eyes of the civilian populace, enabling them to enforce the rule of the U.S.-backed Saigon government and give civilians confidence they could cooperate with and exercise their rights under that regime without fear that the U.S. and allied force would leave and allow Viet Cong cadres to reassert themselves.14

The platoons of the joint U.S.-Vietnamese Combined Action Program lived among the rural populace of South Vietnam. This “credible permanence” allowed villagers in the I Corps area of responsibility to resist the Viet Cong’s efforts to impose its own authority inside the Republic of Vietnam. U.S. Marine Corps History Division

The Combined Action Program was cost-effective and sustainable. By joining the Marines’ professional training and combat enablers—U.S. equipment, logistics, quick reaction forces, artillery and air support, and prompt helicopter medevacs—with the Popular Forces’ motivation and local knowledge, the program fielded a disproportionately large combat force for a small investment of U.S. troops. From 1965 to 1971, among nearly half a million civilians across 800 settlements in the I Corps area of responsibility, the Combined Action Program at its height involved only 2,200 Marines, just 2.8 percent of the 80,000 Marines in Vietnam. But the combined force fielded 20,000 troops in 114 CAPs—more rifle platoons than in a Marine division.15 Its small size notwithstanding, the Combined Action Program resulted in disproportionately more enemy forces killed in action and significantly higher degrees of civilian population security, achieved at half the U.S. casualty rate of Army and Marine Corps units engaged in large-scale combat.16

Strategic Lessons

These and other historical episodes offer much to strategists seeking to develop viable ways of defeating China’s maritime insurgency. So long as China continues to believe its interests are better pursued short of open warfare, Chinese forces will be as constrained as their U.S. counterparts in their ability to compel their opposite numbers to accede to their demands. As in the Asiatic Fleet’s experience, strategies relying principally on deterrence by punishment are weak, favoring a subtle revisionist attacker, while strategies of deterrence by denial—reinforced by promises of larger-scale retaliation in case of attack—are more effective, favoring the defender of the status quo.

An effective deterrence by denial strategy today, focused on protecting civilian mariners at sea, would allow the United States to prevent China from overturning the international regime of maritime law that upholds the freedom of the seas. Such a strategy must be both tactically sound and indefinitely sustainable to have credibility. The inherent economic and political costs of large, protracted foreign deployments, as well as numerical constraints faced by the U.S. Navy’s major combatant fleet, make it imperative for a maritime counterinsurgency campaign to find opportunities for economies of force.

The Combined Action Program demonstrates how large numbers of small U.S. units brigaded with allied forces can produce disproportionate outcomes. International maritime task forces of high-end capital ships could be partially effective in this regard. But the resource constraints of Southeast Asian navies and the large numbers of civilian craft that must be protected mean this dynamic would be more effective at the low end, with a numerically large maritime counterinsurgency force of small vessels. Such a force, supported by agile logistics, land-based aircraft, and a reserve of higher-end combatants to serve as a reaction force in case of attack, would exercise steady influence and control over civilian flotillas, denying China the ability to bend civilian mariners to its will.

To achieve all this will require a campaign that can be sustained for however long it takes Chinese leaders to recognize the inability of maritime insurgency to overturn the rule of international law and the very real benefits to China of accepting and abiding by the existing system of the freedom of the sea. Maritime counterinsurgency has the potential to win a decisive and much-needed victory for the United States, its allies, and the rules-based liberal international order they defend.

[To read the author's accompanying essay, "Why We Defend Free Seas," click here.]