Republican presidential candidate Donald Trump wants to withdraw American forces from Asia and let allies Japan and South Korea defend themselves. He suggests that these two Asian powers might best develop their own nuclear weapons.
Like most American foreign-policy scholars, I think these ideas are fundamentally unsound. They would increase the risk of war between Japan and China in particular, especially during any transition period. They would also greatly weaken the Nuclear Non-Proliferation Treaty, under which nonnuclear countries agree not to pursue the bomb.
But the biggest danger from Trump’s ideas on Asia is the risk of war in the Taiwan Strait. Absent bases in Japan, the U.S. cannot realistically deter Chinese military attacks on Taiwan. This reality could lead China to contemplate the use of force with much less hesitation than it has shown to date.
Knowing this, leaders in Taiwan might seek to develop nuclear weapons of their own as a deterrent. But China has repeatedly stated over the years that Taiwan’s pursuit of the bomb could lead to the very Chinese attack it was designed to prevent.
It is important to review the basics. Since the late 1970s, when the U.S. switched its formal diplomatic recognition to mainland China, it has not treated Taiwan as an independent country. But under the 1979 Taiwan Relations Act, Washington is committed to help Taiwan defend itself against any forceful attempt at reunification by mainland China. The law obligates the U.S., among other things, to consider providing weaponry to Taiwan, and to consider the use of American military power in a conflict.
This is admittedly a somewhat muddled approach to deterrence, lacking the clarity of the NATO Treaty’s Article V mutual-defense clause. But so far it has worked. Even in light of China’s military buildup, it is likely to keep working, since there is little reason for Beijing to roll the dice at present.
China still claims the right to rule Taiwan, and considers the eventual reunification of the mainland with Taiwan a core national interest. Yet it has wisely decided for decades to defer the issue, recognizing the U.S. military deterrent and hoping a political solution would emerge.
This situation is somewhat stable, but delicate. Beijing has repeatedly stated two reasons it would lose patience and use force: a Taiwanese declaration of independence, which would clearly undercut the long-term strategy for reunification that Chinese leaders support, or Taiwanese pursuit of a nuclear-weapons capability.
Thus Taiwan’s leaders would face a huge dilemma if they should be informed by a President Trump that America’s security commitments to East Asia were soon to be dissolved. They might well decide to acquire the bomb.
Taiwan considered going down the nuclear path before. In the mid-1970s, International Atomic Energy Agency officials detected suspicious activities involving a nuclear-research reactor. The U.S. pressured Taiwan to stop any illicit weapons-related activities.
In the late 1980s, Taiwan was again found to be engaged in unwarranted behavior, including initial construction of a facility for reprocessing nuclear fuel.
Taiwan would have powerful incentives to resume these activities if America’s security umbrella, patchy as it may be, is fully withdrawn. While no major Taiwanese politician has openly advocated this, the logic of the situation suggests Taiwan might try to build a bomb clandestinely and declare its deterrent only when it has succeeded. Even if it could pull this off, a Taiwanese nuclear bomb still might not deter a Chinese blockade.
Although Mr. Trump has not weighed in explicitly on Taiwan, there is little chance his strategic views would allow American forces the means to defend it. Lacking bases on Okinawa and other parts of Japan, and presumably not having added any bases in the Philippines or Vietnam, the U.S. would have only two main types of conventional forces: the Navy and long-range bombers.
These capabilities could inflict pain on China. But it would be very difficult for the U.S. to help Taiwan break any Chinese blockade without adequate maritime-patrol aircraft, antisubmarine warfare aircraft, and land-based air superiority and attack jets. China’s increasingly accurate conventionally armed missiles and quieter submarine fleet would make it difficult for U.S. surface ships to break a blockade on their own.
This isn’t an experiment the U.S. should want to run. Leaving Taiwan to rely exclusively on its own means to fend off a Chinese mainland roughly 60 times more populous and 20 times as wealthy would be dangerous. It is the single most fraught consequence of Mr. Trump’s Asia policy.
Mr. O’Hanlon is a senior fellow at the Brookings Institution and author with Jim Steinberg of “Strategic Reassurance and Resolve” (Princeton, 2014).