Can South Korea stay out of war over Taiwan?

As America’s regional allies watched with trepidation, Chinese leader Xi Jinping put Taiwan at the center of his summit with U.S. President Donald Trump on Thursday, pressing Washington to oppose its independence.

Japan quickly sought reassurance from Trump, but South Korea has remained more guarded. Wary of antagonizing China and reluctant to divert attention from the Korean Peninsula, Seoul has traditionally played things safe.

Yet that discretion is becoming harder to sustain with the growing prospect that war over Taiwan could pull the Korean Peninsula into any conflict, regardless of Seoul’s preferences.

“If a direct security threat emerges against us, simply burying our heads in the sand will not make it disappear,” Kim Young-bae, a senior lawmaker from South Korea’s ruling Democratic Party, told The Japan Times ahead of the Xi-Trump summit, referring to a regional crisis involving Taiwan. 

Seoul severed diplomatic relations with Taipei for formal ties with Beijing in 1992.

Such remarks are uncommon from an elected official in South Korea’s progressive camp, especially under incumbent President Lee Jae Myung, who has repeatedly been chided for taking an overly accommodating stance toward Beijing.

China claims the island of 23 million as its own and has not ruled out taking it by force. Beijing maintains that Taiwan is an “internal matter” and rejects outside “interference.”

Kim Young-bae, a senior lawmaker from South Korea’s ruling Democratic Party | KENJI YOSHIDA

Washington has long left open the question of whether it would intervene militarily if the island came under attack — an approach known as “strategic ambiguity” — but is bound by law to supply Taiwan with arms for its defense. 

Trump approved a major weapons package in December but has since kept a second package, worth about $14 billion, as a “negotiating chip” with Beijing.

While South Korea’s main priority should remain stability on the peninsula, Kim said that “over the long term, shifting toward a structure in which Seoul bears primary responsibility for regional contingencies would better serve the overall stability of the alliance.”

“One pillar of Washington’s push to modernize the alliance is the idea that each country should take greater responsibility for its own defense, with South Korea assuming a larger share of the security burden and costs,” Kim said, adding that Seoul needed to prepare for challenges beyond North Korea’s nuclear and missile threats. 

One of the more pressing concerns for Seoul is the risk of emergencies erupting simultaneously in the Taiwan Strait and on the Korean Peninsula — a scenario that recent studies have examined with growing anxiety. 

In March last year, the Brookings Institution warned that a war over Taiwan could pull some U.S. military resources in South Korea away from the peninsula, leaving it more exposed to North Korean provocations. Pyongyang could see an opportunity to escalate while U.S. forces’ attention is elsewhere.

The allies have an understanding of what they call “strategic flexibility,” but much has been kept unsettled. In 2006, Seoul acknowledged the need for U.S. forces stationed in its country to operate beyond the peninsula. Washington, in turn, agreed to respect South Korea’s position that it should not be drawn into a regional conflict “against the will of the Korean people.”

The agreement, however, does not spell out how the allies would handle a Taiwan conflict involving U.S. bases or forces in South Korea.

Hong Tae-hwa, a fellow at the Foreign Policy Research Institute, argues that leaving those questions unanswered is different from deliberately keeping Beijing’s leadership uncertain about Seoul’s intentions.

“Ambiguity over ends — what South Korea’s interests in the strait actually are — is corrosive,” Hong said. “That is strategic evasion, not strategic ambiguity.”

South Korean President Lee Jae Myung gestures as he meets with U.S. President Donald Trump on the sidelines of the Asia-Pacific Economic Cooperation leaders' summit in Gyeongju, South Korea, in October last year. | REUTERS

Hong, who regularly advises South Korean lawmakers on international security, said Seoul should maintain ambiguity publicly over whether U.S. Forces Korea would become involved, but quietly build the operational capacity needed for such a crisis.

That could include Agile Combat Employment, a strategy for dispersing aircraft and personnel across multiple sites to maximize survivability, as well as greater interoperability with aerial-refueling tankers, pre-packaged munitions kits and other capabilities permitting forces to disperse and move quickly.

South Korea, he added, could serve as a rear-area logistics hub moving personnel, fuel and munitions at scale, while tightening military cooperation among the United States and other U.S. regional allies such as Japan, Australia and the Philippines. 

In a crisis involving Taiwan, Washington could seek to use air bases in South Korea such as Osan and Kunsan or facilities at Camp Humphreys to support operations in the region. Even if South Korean forces stayed focused on defending the peninsula, U.S. aircraft, personnel and supplies could still move through bases on South Korean soil.

The South Korean public appears willing to consider at least a limited role. In a 2026 Asan Institute for Policy Studies poll, 39.4% favored nonmilitary assistance in a Taiwan emergency, 15.6% supported rear-area military support and 14% said they would allow U.S. Forces Korea to deploy from the country.

In a sign of the shift in thinking, the top diplomats of Japan, the U.S. and South Korea also reaffirmed the importance of peace and stability across the Taiwan Strait last week — even as Seoul remains comparatively more circumspect about what role it might play in an actual conflict.

To that end, Hong says more must be done to recalibrate South Korea’s current policy over Taiwan.

“Deterrence by uncertainty works when capability and preparation are certain and intent alone is veiled,” he said. 

“Seoul has inverted the formula — reluctance telegraphed, preparation unbuilt, and the only genuine mystery, what Korea actually wants, deters no one.”