Painting from The National Maritime Museum on Wikimedia Commons

Sea Power: Then and Now

Evan Mawdsley—

Sea power is back in the news. In April 2022, the cruiser Moskva was sunk by Ukrainian anti-ship missiles. Since last November, American and British warships have actively defended Red Sea shipping against missiles and drones launched from Houthi-held territory in Yemen. Meanwhile the Fujian, the first full-sized Chinese aircraft carrier, is currently undergoing her sea trials. 

Global sea power has a long history. The two great navies have been, in succession, those of Britain and the United States. British maritime supremacy lasted for some 200 years, until the last years of World War II. The United States, which only began building an ocean-going navy in the 1890s, then achieved supremacy. It made use of the strength of American industry and a mastery of carrier aviation to destroy the Japanese fleet and outbuild and overtake the navy of its British ally; both these developments took place in about 1944.

In the late 1940s, advocates of air power argued that nuclear weapons had made navies – and sea power—a thing of the past. In reality, however, off the coast of Korea and in the Tonkin Gulf sea/air power became an essential tool in the limited wars of containment. The post-war “super-carriers” built from the 1950s onwards came to symbolize the enduring global power of the United States.

What has been remarkable over the decades of American naval dominance is the absence of a full-scale challenge. The era of British maritime supremacy had been different. The Royal Navy had to take into account the persistent rivalry of France and in the end was unable to cope with the upsurge of several “regional” powers with mature industrial economies, including Germany in 1914, the U.S. in the 1920s, and Japan in 1941. For the U.S. Navy after World War II, there were threats, but only asymmetric ones. Russia made no attempt to build aircraft carriers until the declining years of Soviet Russia. (The carrier Admiral Kuznetsov was commissioned in January 1991, eleven months before the disintegration of the USSR.) The Russian weapon of choice was the long-range missile built to be fired from aircraft and warships. None were ever used in anger against American ships (although recently some of these big naval missiles have been fired at Ukrainian cities.)

Over the past two decades or so, the characteristics of sea power have changed. Several elements are involved.

One is the build-up of the Chinese Navy. In sync with the rapid economic development of China and greater engagement with the outside world, naval shipbuilding has greatly expanded. Unlike the Russian case, the Chinese Navy has successfully begun a long-term carrier program. China arguably has the motives and economic resources to carry this through.

However, a certain amount of alarmism and exaggeration is involved in much that is written about the build-up of Chinese sea power. Although the navy of the PRC now has the largest number of warships in the world, this figure includes many small short-range vessels. America’s navy has more large ships and it is capable of operating them at long distances from the United States. Navies take a long time to build, and warships have long shelf-lives. Anticipation of a continuing  build-up by China assumes that country has the stability and patience to sustain the challenge. All in all, the U.S. is unlikely to be overtaken by China in the realm of sea power, and American naval supremacy is likely to continue at least until it reaches its centenary in 2044.

The second change is technological. Sea power has always been affected by innovation. Sailing ships were the initial foundation of British predominance. Later, British strength was based on steam-powered armored ships like the Dreadnought, although they were challenged by torpedo boats and submarines. Similarly, the American drive to naval supremacy came after comprehensive technological change, with the development of naval aviation, especially carrier-based aviation. As already mentioned, long-range cruise missiles and ballistic missiles able to target and attack surface fleets, including carriers, have been in service for decades.

The accelerating rate of technical innovation is, however, notable. Drones and short-range missiles are now available to smaller states. Larger states will be able to deploy pilotless aircraft, ships, and submersibles which, linked by AI, can operate autonomously and in swarms. Whether this will lead to a decisive threat to a big ship like a 100,000-ton nuclear-powered aircraft carrier remains to be seen, but the potential is there.

Finally, what is remarkable about the 21st century is the actual use of ships, missiles, and aircraft in warfare against other fleets, and their evident vulnerability to attack from the land. In the past American task forces had functioned as a simple “containment fleets” or as floating airfields; now they may actually have to defend themselves. Defense of maritime trade—a fundamental feature of sea power— may also become a priority.

The U.S. Navy will probably remain preeminent for the foreseeable future and maintain a broadly similar form to today. However, it will face more potent rivals and need naval allies. And certainly, in our less orderly world, sea power will continue to be of deep importance.


Evan Mawdsley is a historian and former professor of international history at the University of Glasgow. His book, The War for the Seas: A Maritime History of World War II, won the Anderson Medal for the best maritime history in 2019. His latest book, Supremacy at Sea: Task Force 58 and the Central Pacific Victory, is the gripping account of the U.S. Navy’s fast carrier force—and how its Central Pacific campaign in 1944 marked the achievement of American naval supremacy.


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