President Barack Obama believes, as he put it in his third debate with Republican challenger Mitt Romney, that though

we have fewer ships than we did in 1916…we also have fewer horses and bayonets, because the nature of our military's changed. We have these things called aircraft carriers, where planes land on them. We have these ships that go underwater…. The question is not a game of Battleship, where we're counting ships. It's what are our capabilities.

Yes, the army's horses have been superseded by tanks and helicopters, and its bayonets rendered mainly ceremonial by armor and long-range automatic fires, but what, precisely, has superseded ships in the navy? The commander-in-chief has arrived at the epiphany that the ships of today could beat the hell out of those of 1916. To which one could say, like Neil Kinnock, "I know that, Prime Minister," and go on to add that we must configure the navy to face not the dreadnoughts of 1916 but "things called aircraft carriers, where planes land on them," and "ships that go underwater," and also ballistic missiles, land-based aviation, and electronic warfare.

To hold that numbers and mass in war are unnecessary is as dangerous as believing that they are sufficient. Defense contractor Norman Augustine famously observed that at the rate fighter planes are becoming complex and expensive, soon we will be able to build just one. Neither a plane nor a ship, no matter how capable, can be in more than one place at once. And if one ship that is in some ways equivalent to 100 is damaged or lost, we have lost the equivalent of 100. But, in fact, except for advances in situational awareness, missile defense, and the effect of precision-guided munitions in greatly multiplying the target coverage of carrier-launched aircraft, the navy is significantly less capable than it was a relatively short time ago—in anti-submarine warfare, mine warfare, the ability to return ships to battle, and the numbers required to accomplish the tasks of deterrence or war.

For example, Secretary of State Hillary Clinton's diplomacy in the South China Sea is doomed to impotence because it consists entirely of declarations without the backing of sufficient naval potential, even now when China's navy is not half of what it will be in a decade. China's claims, equivalent to American expropriation of Caribbean waters all the way to the coast of Venezuela, are much like Hitler's annexations. But we no longer have bases in the area, our supply lines are attenuated across the vastness of the Pacific, we have much more than decimated our long-range aircraft, and even with a maximum carrier surge our planes would have to battle at least twice as many Chinese fighters.

Not until recently would China have been so aggressive in the South China Sea, but it has a plan, which is to grow; we have a plan, which is to shrink; and you get what you pay for. To wit, China is purposefully, efficiently, and successfully modernizing its forces and often accepting reductions in favor of quality. And yet, to touch upon just a few examples, whereas 20 years ago it possessed one ballistic missile submarine and the U.S. 34, now it has three (with two in the ways) and the U.S. 14. Over the same span, China has gone from 94 to 71 submarines in total, while the U.S. has gone from 121 to 71. Ours are better, but as ours become fewer China's are catching up and increasing in number.

The effect in principal surface warships is yet more pronounced. While China has risen from 56 to 78, the U.S. has descended from 207 to 114. In addition to parities, China is successfully focusing on exactly what it needs—terminal ballistic missile guidance, super-fast torpedoes and wave-skimming missiles, swarms of ocean-going missile craft, battle-picture blinding—to address American vulnerabilities, while our counters are insufficient or non-existent.

Nor is China our only potential naval adversary, and with aircraft, surface-to-surface missiles, and over-the-horizon radars the littoral countries need not have navies to assert themselves over millions of square miles of sea. Even the Somali pirates, with only outboard motors, skiffs, rocket-propelled grenades, and Kalashnikovs, have taxed the maritime forces of the leading naval states.

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What, then, is a relatively safe number of highly capable ships appropriate for the world's richest country and leading naval power? Not the less than 300 at present, or the 200 to which we are headed, and not 330 or 350 either, but 600, as in the 1980s. Then, we were facing the Soviet Union, but now China, better suited as a maritime power, is rising faster than the United States at present is willing to face.

The trend lines are obvious and alarming, but in addition we face a potentially explosive accelerant of which the president is probably blissfully unaware, as is perhaps even his secretary of the navy who, as he dutifully guts his force, travels with an entourage befitting Kubla Khan, or at least Kubla Khan, Jr. That is that whereas the American Shipbuilding Association (now dissolved) counted six major yards, China has more than 100. Whenever China becomes confident of the maturation of its naval weapons systems, it can surge production and leave us as far behind as once we left the Axis and Japan. Its navy will be able to dominate the oceans and cruise in strength off our coasts, reversing roles to its pleasure and our peril—unless we attend to the navy, in quality, numbers, and without delay.

This would demand a president who, like Ronald Reagan, would damn the political torpedoes and back a secretary of the navy who, like John Lehman, would unashamedly and with every power of rhetoric and persistence rebuild the fleets. The military balance, the poise of the international system, and the peace of the world require no less. Nor does America deserve less. But in the next four years it will get less, much less, from an American administration that—perhaps uniquely in our history—neither understands nor trusts American power.