Mr. Obama, like his predecessors, seems now to be embracing a militarized policy with regard to China, the sinew of which is a global network of military bases that has changed little since the peak of the cold war. Far from reducing its profile in Asia, the Pentagon has been quietly enhancing or reconfiguring its capacity there in recent decades. For example, it has been building up forces on the United States territory of Guam, a far-reaching strategic enclave in the Pacific much like the British island of Diego Garcia in the Indian Ocean. Pentagon strategists say the aim is to “dissuade, deter and defeat” regional aggressors. And in recent months, the Defense Department has been developing a strategy for Asia called “AirSea Battle,” an instrument with which American military power can address “asymmetrical threats in the Western Pacific,” an implicit reference to China.

Washington justifies its Pacific buildup by citing China’s increasingly menacing claims on the region’s contested waterways. But there has been no serious American-led effort to resolve such disputes through bilateral or multilateral diplomatic rounds.

Indeed, America’s top diplomat has become the chief civilian advocate for military answers to diplomatic challenges. Speaking in Honolulu last month, Secretary of State Hillary Rodham Clinton called for “a more broadly distributed military presence” in Asia. While in Manila, she appeared on an American warship and reaffirmed the nearly 60-year-old security pact between the United States and the Philippines. She also has endorsed the creation of an American-led regional trade pact that pointedly excludes China for the present, a remarkably petty snub compared to the way her legendary predecessor George C. Marshall offered (without success, in the face of Stalin’s suspicions) to include the Soviet Union in the postwar reconstruction plan that now bears Marshall’s name. And this month she visited Myanmar, where the Obama administration has assiduously worked to neutralize a corrupt and repressive government in favor of democratic reform; in the grander strategic game, this, too, could be read in Beijing as a tactic to weave the country — which has been Beijing’s ally — into an American noose around China.

Since the end of the cold war, senior diplomats and general officers have coalesced in support of a central military role in the formulation and execution of foreign affairs. This role is a consequence of the growing imbalance between America’s diplomatic and military resources, and it shaped lamentably militarized responses to the Balkan crisis of the 1990s, the 9/11 attacks, the reconstitution of Iraq and now the rise of China. Mrs. Clinton may declare herself, as she did in an October article in Foreign Policy and again in Honolulu, to be for “a substantially increased investment — diplomatic, economic, strategic and otherwise” in the Asia-Pacific region, but this ignores the fact that the country’s diplomatic capacity has been cruelly cut back over the last two decades, particularly in relation to the Pentagon’s.

In fact, the Pentagon can be expected to keep outspending the State Department at an enormous rate — even in the unlikely event that Congress musters the courage to impose draconian budget cuts, as the law requires, in the wake of the deficit-reduction super committee’s collapse. Currently, Washington is allocating about a dozen dollars for defense outlays for every dollar it spends on diplomacy and international assistance. In Honolulu, Mrs. Clinton also celebrated the “opportunities and obligations” in Asia that are ripe for exploration after the immense expenditure of American blood and coin in Iraq and Afghanistan. That recalls the way the country’s policy making elite saw fresh dangers as well as opportunities in Asia after America’s withdrawal from Vietnam — an earlier example of Washington’s cyclical preoccupation with perceived threats from one end of the Eastern Hemisphere to the other.