US Strategists on the Advantages and Limitations of Sea Power

As the specter of war hovers over the South China Sea, two U.S. strategists have written articles in respected military journals examining the strengths and limits of a maritime strategy vis-a-vis China. The Biden administration would be wise to ponder both pieces as it grapples with increased tensions over the status of Taiwan and the longer-term Cold War with China.

In the February 2022 issue of Proceedings, the journal of the U.S. Naval Institute, Thomas Mahnken, president of the Center for Strategic and Budgetary Assessments and a former deputy assistant secretary of defense (including a stint in the department’s Office of Net Assessment), proposes a maritime strategy to deter and, if necessary, defeat China in a war in the South China Sea. His article is entitled “A Maritime Strategy to Deal with China.” In the Autumn 2021 issue of the Naval War College Review, Professor Jakub Grygiel, a former senior adviser to the State Department’s Policy Planning office and co-author of “The Unquiet Frontier” (which I reviewed in the Asian Review of Books) authored an essay entitled “The Limits of Sea Power.”

Mahnken bases his proposed maritime strategy on the geographical barrier known as the “first island chain,” which consists of Japan, Taiwan, the Philippines, and peninsular Southeast Asia. The United States, he writes, should treat the first island chain as the Fulda Gap of the Asia-Pacific region (referring to the intra-German border between NATO and the Warsaw Pact). The United States and its regional allies must defend this maritime terrain with “land-based, expeditionary, naval, and air forces” supported by cyber and space assets, Mahnken argues.

He urges U.S. policymakers to deploy “inside forces” on the first island chain and sea-based “outside forces” to both support the inside forces and to “threaten China from multiple axes.” He believes that a sufficiently armed and geographically situated maritime strategy will cause China to rethink its strategy for politically or militarily annexing Taiwan, and failing that, will enable the United States and its allies to achieve victory in the event of war.

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Grygiel’s article on “The Limits of Sea Power” includes historical examples of both the strategic advantages and limitations of maritime power in wars and international relations, from ancient Athens to Venice to the Crusades, and more recently to Great Britain’s rise, the First and Second World Wars, and the Cold War. Grygiel invokes Themistocles, Pericles, John Adams, Alfred Thayer Mahan, Julian Corbett, Halford Mackinder, Nicholas Spykman, and other strategic thinkers to support his contentions. Grygiel contends that China’s challenge to the U.S.-led world order is both maritime and continental, which exposes some of the limits of sea power that the United States needs to consider in developing strategies to win what some have called this second Cold War.

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Grygiel notes that the “strategic advantage of the seas ebbs and flows in history. Land communications are not perennially inferior and sea-lanes are not inexorably ascendant in strategic value.” And, as he notes, it is not easy for a maritime power to translate its supremacy at sea into “political influence on land.” This is why the great power struggles throughout history were rarely straight land power vs. sea power conflicts. Instead, land powers and sea powers alike looked for allies that could enable them to wage war effectively across both elements of power. Great Britain, for example, for centuries supported continental coalitions to offset the greatest continental land powers. In the same way, since 1945, the United States has formed alliances with continental powers on the Eurasian landmass to maintain the geopolitical pluralism of Eurasia.

Great continental land powers, like Napoleon’s France and Hitler’s Germany, in their bids for world empire sought sea power allies and control over coastal regions. Grygiel notes Napoleon’s statement that he would “conquer the sea through the power of land.” As the French Emperor reportedly said, “Make us masters of the [English] Channel and we will be masters of the world” – thus, his alliance with Spain and his erection of the Continental System. Hitler, meanwhile, conquered coastal France and allied with Italy to wage maritime warfare in the Atlantic and the Mediterranean. Both great powers faltered when they failed to consolidate effective political control of Eurasia thanks to Russian land power supported by the sea powers of Great Britain and the United States.

This geopolitical reality is why Mackinder’s concept of the World Island in “Democratic Ideals and Reality” was and is so important. Mackinder’s World Island combines effective political control of the Eurasian-African landmass with geopolitical insularity, enabling a power or alliances of powers based in Eurasia to be supreme both on land and at sea.

Mackinder has often been misinterpreted as a proponent of land power, when he actually recognized that great sea powers require sufficient land bases, while great land powers can use their resources to outflank sea powers. That was the meaning behind his famous question: “What if the Great Continent, the whole World-Island or a large part of it, were at some future time to become a single and united base of sea-power? Would not the other insular bases be outbuilt as regards ships and outmanned as regards seamen? Their fleets would no doubt fight with all the heroism begotten of their histories, but the end would be fated.”

Grygiel argues that sea powers have three options to influence continental geopolitics to avoid succumbing to Mackinder’s nightmare: First, establishing a presence in the land powers’ coastal regions (usually in coordination with allies); second, imposing pressure (economic, military, and political) on the enemy’s land borders; and third, exercising control over inland seas. During most of the Cold War against the Soviet Union, the United States used the first option by forming alliances with continental powers that enabled the stationing of large numbers of U.S. forces in Eurasia’s coastal regions. Arguably, in the 1980s under President Ronald Reagan, Washington combined the first and second options by adding economic, political, and military pressure to the border areas of the Soviet empire.

“The grip of sea powers over the continents is precarious, even when they dominate the oceans,” Grygiel warns. Their continental alliances can weaken or wane, thereby reducing the sea power’s continental presence. And continental powers can become less vulnerable to disruption at sea. These two variables, he believes, are crucial in the current conflict with China.

The United States has a relatively small continental presence in East Asia on the Korean Peninsula, but it also has a significant offshore presence in Japan and a lesser presence in Guam, the Philippines, and Australia. It has a close security relationship with Singapore and is seeking additional military bases on islands in the Indian Ocean as India-U.S. cooperation expands in the face of China’s rise. And the United States is improving relations with its old foe Vietnam, whose leaders also fear China’s ambitions. But these are mostly sea power or maritime assets.

China is today vulnerable to sea power disruption along the maritime highway that stretches from the East and South China Sea to Eastern Africa and the Mediterranean Sea, by which its economy is supplied and fueled. But Grygiel notes that China’s Belt and Road Initiative (BRI) is partly continental and seeks to open or improve land routes across the Eurasian landmass. He writes, “[I]f Beijing firms up its control over land routes linking China with the rest of Eurasia, creating a continental core, American naval forces floating in the Pacific Ocean will have considerably less effect on its decisions and behavior.”

In defeating the challenges of Napoleon’s France and Hitler’s Germany, the sea powers of Britain and the United States needed Russia as an ally and co-belligerent. Today, the “great geopolitical question for the United States,” Grygiel writes, “is whether Russia will be more aligned with China – establishing a continental entente – rather than maintaining a lengthy land frontier of friction.” Unfortunately, and due in no small part to the policies of the Biden administration, Grygiel’s question has been answered at least for now: China and Russia have formed a strategic partnership that threatens to upend the U.S.-led world order. This development exposes “the limits of sea power.”

Grygiel presumably would add a land power component to Mahnken’s maritime strategy to effectively contain or defeat China. Such a strategy would include a strengthened alliance with India and efforts to drive a wedge between China and Russia, as President Richard Nixon did in the early 1970s. The important takeaway from these two important articles is that U.S. strategy toward China, especially in the immediate future, will lean heavily on the maritime power side, but in the long term Washington neglects the land power component at its peril.