American Deterrence in the Western Pacific: What the US Navy Can and Cannot Do
The United States has maintained a policy of strategic ambiguity toward Taiwan for more than four decades. It does not formally recognize Taiwan as an independent state. It does not provide a treaty guarantee equivalent to the commitments it has made to Japan, South Korea, or NATO allies. It does sell Taiwan defensive weapons under the Taiwan Relations Act, and it maintains unofficial relations through the American Institute in Taiwan. What it has not done is say explicitly and publicly whether it would use military force to defend Taiwan against a Chinese attack. This ambiguity has been the foundation of American cross-strait policy since 1979, and it has been under increasing strain as the military balance in the strait has shifted.
The naval capability that underlies American deterrence in the western Pacific has not degraded in absolute terms. The US Navy operates the most capable surface combatants, submarines, and carrier aviation in the world by most operational metrics. What has changed is the relative balance. The PLA Navy has grown from a coastal defense force into a genuine blue-water navy with surface combatants, submarines, and carrier aviation that approach American capabilities in quantity and, in some specific areas, in quality. The combat radius of Chinese anti-ship missiles — the DF-21D and DF-26 carrier-killer ballistic missiles — has created contested operating zones in the western Pacific where American carriers cannot operate freely without accepting unacceptable risk.
The A2/AD problem — anti-access/area denial — is the central operational challenge for American naval planners in a Taiwan contingency. Chinese investments in long-range anti-ship missiles, integrated air defense systems, and over-the-horizon radar have created a layered defense environment that pushes American surface forces away from the strait at exactly the moment when proximity would be most militarily relevant. A carrier that must operate 500 miles from the strait to avoid missile threat envelopes cannot provide the same level of close air support to Taiwan’s defenses as a carrier 100 miles away. The operational geometry favors the defender — China — in ways that were not true fifteen years ago.
American submarines are the capability that most persistently complicates Chinese strategic planning. Virginia-class nuclear attack submarines operating in the western Pacific can threaten Chinese surface combatants, amphibious shipping, and logistics vessels without entering the threat envelopes that constrain surface operations. The PLA’s antisubmarine warfare capability has improved significantly over the past decade but remains a relative weakness compared to its surface and air capabilities. In a strait conflict, American submarine operations would be the most effective instrument for directly engaging the PLA crossing force. They would also be the most escalatory single military action short of strikes on the Chinese mainland.
The basing structure that enables American power projection in the western Pacific has become more distributed and more contested simultaneously. Andersen Air Force Base on Guam and Kadena Air Base in Okinawa are within range of PLA ballistic missiles. The Philippine basing arrangements reopened under the Marcos administration have added operating locations closer to the strait, but these facilities are within even shorter range of Chinese strike systems. The operational survivability of American forces in fixed bases in the western Pacific during the opening phase of a PLA strike campaign is a problem that American planners have invested heavily in addressing and have not fully resolved.
The alliance network is the dimension of American capability that pure military capability metrics most consistently understate. Japan’s Self-Defense Forces, operating from bases throughout the Ryukyu chain, can threaten Chinese maritime operations in the East China Sea and the northern approaches to the strait from positions that China must account for in any operational plan. Japan’s hosting of American forces provides basing options that are more geographically favorable than anything the US owns in the region. Whether Japan would authorize the use of those bases in a Taiwan contingency is a political question that has been answered more clearly in the affirmative under recent administrations than at any previous point.
The deterrence equation is not broken. It is less favorable than it was, by a margin that is contested among analysts but that is real. Maintaining it requires continued investment, continued alliance management, and continued clarity about what the United States will actually do when tested — a clarity that strategic ambiguity, by design, withholds.