Much has changed in the U.S.-China relationship over the past three decades as China has increased its global economic and political influence, built modern military forces, and grown to be the world’s second-largest economy. One thing that has not changed, however, is that Taiwan is still the most likely trigger of a U.S.-China war.

There are many irritants in U.S.-China relations, but very few things that would foment a military conflict. China and the United States will not go to war against each other over the People’s Republic of China’s (PRC) economic coercion, spy balloons, U.S. restrictions on the sale of advanced technology to China, Chinese cyber-theft, repression in Xinjiang and Hong Kong, China holding U.S. citizens as hostages, China’s rapid economic growth, alleged U.S. attempts to subvert the Chinese government, U.S. security cooperation in the region, a Chinese naval base in one of the Pacific island states, statements by Americans that “hurt the feelings of the Chinese people,” or China’s nuclear weapons buildup.

The South China Sea deserves mention as a “flashpoint.” An incident between U.S. and Chinese ships or aircraft could escalate into hostilities. Generally, however, Beijing is maintaining if not gradually gaining ground, and this trend is unaffected by occasional U.S. “freedom of navigation” sail-bys. 

A war on the Korean Peninsula could result in Chinese and U.S. forces shooting at each other, but only if both sides took a series of wrong turns.

In general, three contingencies would cause Beijing to consider going to war. The first is the emergence of a situation that endangers the Chinese Communist Party’s (CCP) monopoly over political power in China and that could be neutralized by opting for war. The second is the killing of PRC nationals by operatives of a foreign government. Probably a large number; note that the bombing of the Chinese Embassy in Belgrade in 1999 by U.S. aircraft, which killed three Chinese, did not lead to U.S.-China hostilities. A third possible casus belli would be foreign seizure of what Beijing considers to be Chinese territory.

Two of these contingencies would apply to Taiwan. The narrative built by the CCP forces it to resist at all costs the permanent political separation of Taiwan from China, or else the party by its own criteria proves itself unfit to rule China. Faced with a choice between fighting a war it did not think it could win and acquiescing to Taiwan’s independence, the regime would likely see the former as offering the better chance of keeping the CCP in power.

Beijing also defines Taiwan as Chinese territory that would be “lost” if it became the Republic of Taiwan—particularly valuable territory, as Taiwan by itself is the world’s twentieth-largest economy.

For the United States, the most likely path to a war on the western rim of the Pacific Ocean is the need to defend a friend or ally that is under attack. Although not an ally, Taiwan is a U.S. protectorate, and U.S. ally Japan has a vital interest in Taiwan remaining free of PRC control.

There are at least three crucial variables at play. The first is Taipei’s cross-Strait policy—whether it remains cautious or openly drives toward de jure independence. The second variable is Beijing’s assessment of what actions by Taiwan would constitute intolerable movement toward independence. The third variable is China’s perception of U.S. intentions toward Taiwan: whether Washington is pushing for or trying to restrain independence. A final important variable is the cross-Strait military balance. Although the certainty of winning is not the determinative issue for Beijing, it would be easier for China to opt for war if the chances of operational success are high rather than low.

How Washington, Taipei, and Beijing manage the cross-Strait dispute will make the difference between a U.S.-China war probably occurring and probably not occurring in the near future.

Denny Roy is a Senior Fellow at the East-West Center in Honolulu.

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