Will North Korea Defend China in a Taiwan War?

In his recent visit to South Korea, U.S. Secretary of War Pete Hegseth affirmed that U.S. troops based in the country could be used to deter regional threats, the most important being a Taiwan contingency. South Korea has balked at the U.S. suggestion, but considering the U.S. pivot to homeland defence, the pressure on South Korea to contribute to U.S. regional deterrence will only increase.

Article II reads:

What is missing from the clause is who started the shooting. The ambiguity leaves open the possibility of China coming to North Korea’s defence if a North Korean invasion of the South turns awry due to a U.S.-South Korean retaliation.

Indeed, this is what happened in 1950 when China intervened to save North Korea after its invasion led to a U.S.-South Korea march north. The ambiguity is because of the Sino-Soviet Split. China, out of its ambition to detach North Korea from the Soviet orbit, did not insert a strong escape clause to disincentivise a North Korean first strike.

The collapse of the Soviet Union allowed China to scale back some of its security commitment to North Korea. In 2017, amid the U.S.-North Korea nuclear brinkmanship, China curtailed this ambiguity by telling North Korea that Beijing would not rescue North Korea if it attacked the United States first. North Korea however has not made any public statements regarding the new interpretation of Article II. The treaty renewal in 2021 did not reflect this interpretation of the Chinese commitment.

A U.S. intervention against a Chinese invasion of Taiwan technically subjects China to an armed attack under the treaty’s purview. There is little escape room for Pyongyang because it recognises Taiwan to be a part of China and the treaty scope covers the “Far East”. Even if China starts the shooting, North Korea is still obligated to defend it as the text of Article II has not changed. Russia started the invasion of Ukraine, but North Korea helped it anyways.

However, Pyongyang cannot significantly divert its military power away from the Korean peninsula, for a related reason to explain Seoul’s dubious response to the expansion of the USFK mission. North Korea’s navy is no match for that of the U.S.-South Korea-Japan bloc and it lacks maritime power projection capability to be useful for a Chinese invasion of Taiwan. North Korea also doesn’t want to launch missile attacks against U.S. regional bases in South Korea, Japan, the Philippines, or Guam for fear of retaliation. Pyongyang’s rejection of unification also means it will not exploit the USFK distraction to conquer Seoul by force as the South Korean military alone is still superior to the North Korean military. “By all means at its disposal” doesn’t necessarily mean North Korea will restart the Korean war.

The most cost-effective way for Pyongyang to meet its treaty obligation without being entrapped into a regional war is to launch low-level provocations against Seoul to pin down the USFK. These provocations may include propaganda broadcasts along the border, drone incursions, intrusion of South Korean water near the Northern Limit Line, leaflet droppings, or missile tests. Low-level provocations can overburden South Korean and USFK facilities and stretch the allied reconnaissance capability. The United States, distracted by Taiwan, will not invade or encourage Seoul to respond forcefully to Pyongyang’s low-level provocations.

China is likely to support North Korea’s low-level provocations because they can keep Washington distracted without provoking a full-scale conflict involving China in Korea. With China’s approval, North Korean troops can help pacify Taiwan and learn how the United States fights a war in the Pacific. These provocations matter not only militarily but they will also help North Korea drive a hard bargain with Washington, Seoul, and Beijing, just like it is doing with Moscow thanks to its military presence in Kursk.

It is important to stress that the level of North Korean provocations may be coordinated pre-invasion so that both China and North Korea can avoid any misunderstanding of obligation or miscalculation of escalation risk. China and North Korea will also see if the South Korean military is involved in a Taiwan contingency to determine the appropriate level of escalation. Russia’s invasion of Ukraine has become a boon for North Korea. It will similarly look to benefit from a China’s invasion of Taiwan.

Khang Vu is a visiting scholar in the Political Science Department at Boston College. He was a 2023-24 Hans J. Morgenthau pre-doctoral fellow at the University of Notre Dame. Khang received his Ph.D. from Boston College in 2024 and his master’s degree from Dartmouth College in 2019.

This article appeared originally at Lowy Institute's the interpreter.