The US can't deter an attack on Taiwan

If the United States can’t deter Beijing, it is likely that sometime within the next six years Taiwan will be “liberated” by the People’s Liberation Army (PLA). And as things currently stand, the U.S. can’t deter Beijing. So within the next six years, Taiwan will be “liberated.”

Although it can be complicated in practice, deterring a conventional attack of the kind Beijing is likely to launch against Taiwan is in theory very simple. All that the United States needs to do is raise the anticipated cost of a Chinese conventional attack to the point where it exceeds the benefits Beijing might realistically hope to gain from such an attack.

Confronted with such a cost-benefit calculus, China’s leadership would have a powerful disincentive to use military force to attack Taiwan. It would, in other words, be effectively deterred.

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And for most of the period since Chiang Kai-shek’s nationalist forces retreated to the island in 1949, the combined forces of Taiwan and the United States have done just that.

Three factors were key to deterring China from attacking Taiwan. First, with U.S. support, Taiwan’s armed forces during this period were sufficiently strong to deny the PLA any realistic possibility of conducting a successful amphibious assault on Taiwan. The combination of Chinese military weakness – the PLA was neither organized nor equipped for serious amphibious operations – and Taiwanese-American conventional military strength meant that Beijing was dissuaded from even attempting to use military force to compel Taiwan to return to the fold.

Second, for most of this period Beijing’s level of motivation was in any case relatively low. To
be sure, the recovery of all the nation’s historical territory, including Taiwan, has been part of the Chinese Communist Party's (CCP) raison d’être since the founding of the People’s Republic. But for the most part – and especially during the period of “peaceful rise” diplomacy initiated by Deng Xiaoping – this was a background aspiration rather than a pressing concern.

Finally, cross-strait conventional deterrence was effectively backstopped by U.S. nuclear
weapons. As China became wealthier and more militarily capable, deterrence was upheld by the possibility that any attempt to use conventional military force to liberate Taiwan might escalate to the point where the U.S. would be forced to use nuclear weapons to defend the island.

Given the United States’s overwhelming nuclear superiority during this era, and the credibility this lent to its implicit nuclear threat, this meant that the potential costs to Beijing of any cross-strait invasion were simply so high that no anticipated political benefit could justify the risk.

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Fast forward to today. Now, none of these conditions remain in place. Consider the changed conventional military balance. Beijing did not like having to back down during the Third Taiwan Strait Crisis in 1996 when the United States sent two carrier strike groups to Taiwan to deter Chinese aggression. It has spent the quarter-century since then modernizing its military so that it would never find itself in a similar situation again.

These modernization efforts were aimed specifically at enabling the Chinese air force, navy, army and strategic rocket force to blockade Taiwan, deny U.S. forces access to the region and ultimately to launch amphibious operations against the island. No one seriously doubts that these efforts have paid dividends or that China’s military is now capable – or very nearly capable – of conducting high-tempo, full-spectrum operations against U.S. forces in the region. And no one doubts they could easily defeat Taiwan’s meager military.

The result: a dramatic shift of the correlation of conventional forces in China’s favor. Indeed, so dramatic has this shift been that Chinese President Xi Jinping and China’s top brass now believe that China can prevail militarily, even if the U.S. intervenes, and do so at an acceptable military cost.

Next consider changes in the perceived benefits to Beijing of successfully liberating Taiwan.
Viewed from the perspective of China’s internal politics, those benefits are considerable. Xi and the Party have both increasingly staked their legitimacy – and in Xi’s case, his legacy – on the project of national rejuvenation, a project that includes reaching a certain level of economic prosperity, but also political goals such “moving to the center stage” of world politics and reunifying the nation that was “split” by foreign imperialism and civil war.

This being the case, the political cost of allowing Taiwan to remain outside the fold, now that China is relatively wealthy and powerful and thus able to compel its return, is growing. Indeed, if Chinese public opinion is any indicator, the political benefits of forcibly compelling Taiwan’s reunification now clearly exceed the costs. Doing nothing – the official policy for most of the period before China’s rise and Xi’s accession – is a decreasingly viable option.

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Taken together, these two sets of developments – benefits and incentives rapidly rising, costs and disincentives substantially declining – would seem to have shifted Beijing’s cost-benefit calculus decisively in the direction of invasion. The needle, to put it bluntly, would seem to have swung sharply in the direction of “attack.”

Not to worry, though, one might argue. Any such invasion would have the potential to draw the United States into the conflict, and that in turn carries with it the risk of escalation to the point of nuclear war. Given that existential risk, surely the needle remains firmly pointed in the direction of “don’t attack.”

And that leads us to the final, and decisive, shift in the strategic correlation of forces — changes in the nuclear balance. As China has expanded its nuclear missile force and otherwise taken steps to realize strategic parity with the U.S., Washington’s nuclear backstop has become less credible (that’s the whole point of China’s nuclear buildup).

In fact, we have now reached a point in the nuclear relationship where the so-called “stability-instability paradox” has begun to kick in. The stability-instability paradox holds that as two states achieve rough nuclear parity (or at least the ability to inflict mutual assured destruction on one another), they feel more confident in engaging in conventional military competition and even conflict.

As this is now undeniably the case between the United States and China, all that really matters going forward is the U.S. conventional deterrent — the ability to deny China success on the conventional battlefield. And that deterrent is simply no longer fit for purpose.

Does this mean that the PRC will “liberate” Taiwan anytime soon? Probably not. The PLA is not yet ready to launch a full-scale amphibious assault and will likely not be ready for a few years. But it does mean that Washington cannot count on the policies and platitudes of the past to deter Beijing for much longer. It means that when it comes to Taiwan, the United States must decide: take steps now to restore deterrence or prepare to see Taiwan “liberated” in the not too distant future.

Andrew Latham is a professor of international relations at Macalester College in St. Paul, Minn., and a non-resident fellow at Defense Priorities, a Washington, D.C., think tank.