Not only will the 21st century be an Asian century, but it will also be a naval century, according to Robert Kaplan’s new book Asia’s Cauldron: The South China Sea and the End of a Stable Pacific. The heart of this naval century will be the South China Sea, where China converges with the Indian subcontinent: a place of trade and fishing, of underwater energy deposits, of clashing territorial claims, of nationalism, and, perhaps, of great conflict. The story of this sea and all its conjoined civilizations will not be unraveled outside the American story, but within it.

Since the end of the 19th century, the United States has had a presence in Asia. Today it circulates as many as six carrier strike groups throughout the region and has bound itself to defend its Asian allies: South Korea, Japan, the Philippines, Australia, and, to some extent, Taiwan. President Obama recently completed a tour of the region during which he sought to assure allies that the United States is there for them. But as nationalisms collide in East Asia, and a rising China seeks its historical sphere of influence, the end of the story is by no means clear. Will the balance of power shift peacefully? Or will there be conflicts and fitful wars, with the United States as a party?

If China rises in the 21st century as America rose in the 19th and 20th, conflict in East Asia is likely, Kaplan warns. In its rise, the United States sought to exclude European powers from the Americas and to acquire additional territories. Manifest Destiny, the Monroe Doctrine, the Mexican-American War, and the Spanish-American War were all part of this process. The United States became a regional hegemon through the force of its arms, as John Mearsheimer of the University of Chicago has argued. Today, a rising China is seeking regional hegemony in East Asia. If it acts as the United States acted, it will seek to exclude extra-regional powers (i.e., the United States), spread its influence, and acquire disputed territories.

Like the United States sought to dominate the Caribbean, the sea in its backyard, so China desires to dominate the South China Sea. The incentives are not simply geographic. The Malacca Strait, Kaplan wisely observes, is the equivalent to the Panama Canal: a gateway of trade, yet also a place for potential instability—a place China must guard in order to protect the valuable shipments of energy that pass through it. China also has powerful historical motivations, motivations the United States did not have, to project its influence. For millennia China was a great civilization and power. But beginning in the 19th century, this came to an end. Western powers humiliated and divided China even as it fought the bloodiest revolution in world history (the Taiping Rebellion). Then the Japanese began half a century of exploitation and destruction. Finally, Mao himself devastated China. Only since the time of Deng Xiaoping’s preeminence—some 35 years—has China begun to recover. And the Chinese say: “never again.” China will be strong; it will once again become East Asia’s great power.

Yet as China slowly seeks to dominate its Caribbean, it encounters a problem. America’s alliances in East Asia guarantee the security of nations like the Philippines and Japan, and support others like Taiwan. Furthermore, nationalism is the animating force of East Asian politics, and at the heart of nationalism is land. In East Asia, this takes the form of rivalrous claims over uninhabited and often submerged lands (notably the Pratas, Paracel, and Spratly Islands in the South China Sea, the Senkaku/Diaoyu in the East China Sea, and Dokdo/Takeshima in the Sea of Japan). The islands themselves have little value. There are rumored to be great energy reserves submerged in the seas, but this remains uncertain. More immediately important, their fertile fishing grounds give maritime control greater importance. Nonetheless, claims of sovereignty can mobilize the passions of entire nations. That the disputes will be settled outside of international law seems quite certain: the competing legal and historical claims for territorial rights (12 miles) and exclusive economic zones (200 miles) do not seem capable of legal adjudication. This makes the realities of hard power more important than ever.

Much has been made in the Western media of the U-shaped “nine-dashed line,” by which China claims most of the South China Sea. The general impression given by most discussions of it is that the Chinese claim is unreasonable and zero sum. Kaplan rights this misperception. The line, as it turns out, was originally a Guomindang concept (the Guomindang fled to Taiwan after being defeated in the Chinese Civil War), and it originally had 11 dashes. Zhou Enlai, Premier of the People’s Republic of China from 1949 to 1976, had the two dashes that claimed the Gulf of Tonkin removed in 1953. Subsequent negotiations over 27 years finally resolved the dispute in December of 2000: China and Vietnam agreed to an equidistant territorial division. Today, Vietnam and China are conducting joint explorations for energy resources in the Gulf. China, meanwhile, is seeking economic and territorial rights in the area covered by the other nine dashes at the expense of its maritime neighbors. But that an 11-dashed line can become a nine-dashed line should give China’s neighbors reason for hope: that is, if they are willing to compromise (and negotiate in good faith for decades).

The rise of the United States was relatively peaceful because England, America’s great-power rival, decided to accommodate the United States by accepting its regional dominance. England, as the United States is today, was then the world’s greatest naval power. Its leaders saw America’s rapidly growing regional economic influence and acknowledged the geographical reality that the United States was close to the Caribbean and England was far from it. Its leaders also acknowledged the geopolitical reality that American interests would always be stronger than British interests in the region. For good reason Grover Cleveland’s Secretary of State, Richard Olney, could in 1895 declare the United States to be “practically sovereign” in the Greater Caribbean.

It seems clear China would like to make the same declaration someday. If the United States chooses to accommodate China, granting it its own mare nostrum (as the Romans called the Mediterranean), there likely will be great-power peace, as in America’s rise. But if the United States, motivated by legalism, moralism, or purported realism chooses to confront or contain a rising China, conflict seems inevitable. And as in America’s own case, the regional power has every advantage: geographic proximity, economic interdependence, historical prerogatives, and democratic nationalism.

Asia’s Cauldron has introduced the scenario: in an Asian century, where warships are the denomination of power, China is rising. What role the United States will play in this story is unclear. What is clear is that the choice to accommodate or contain is the most important geopolitical decision American policymakers will make in this generation.

Jared McKinney received his M.S. (with Distinction) in Defense and Strategic Studies from Missouri State University (Fairfax, VA) in May 2014.