Amid new Trump era, South Korea considers ‘plan B’ – building its own nuclear weapons

WASHINGTON − Building nuclear weapons could be South Korea's "plan B" in an increasingly "unpredictable" security landscape, Seoul's top diplomat told the country's legislature Wednesday.

The remarks from Foriegn Minister Cho Tae-yul signal that the U.S. ally could back away from Seoul's recent Biden-era commitment not to develop nuclear weapons.

NK News was the first English-language outlet to report Cho's speech, which comes amid the early weeks of President Donald Trump's second administration.

Although Cho himself noted his discussion of the nuclear plan B is "premature," some in Seoul question whether Trump is willing to uphold America's promise to defend its ally − with nuclear weapons if necessary − against a nuclear-armed North Korea. (Secretary of State Marco Rubio released a joint statement with Cho and Japan's top diplomat Feb. 15 after a meeting "to reaffirm the unshakable" partnership between the countries.)

A top expert on Washington-Seoul relations, Victor Cha of Georgetown University and the Center for Strategic and International Studies think tank, downplayed the significance of Cho's remarks.

"It would be natural for a Korean official to say all options are on the table at this time of great uncertainty," Cha told USA TODAY. "In the end, such decisions about going nuclear would only be made in response to some major change in the U.S. security commitment to Korea." Cha further noted that Trump officials thus far "are not trending" toward a reduction in security support.

Yet a majority of South Koreans support the idea of developing an independent nuclear arsenal, according to Cha's research. The idea lacked comparable support among Seoul's "strategic elite" in a 2024 survey Cha and his colleagues conducted before the U.S. presidential election.

The debate over nuclearization in South Korea is sharply politicized as well. Support for weapons development is high among members of the ruling conservative People's Power Party, which is likely to lose power in upcoming elections after impeached President Yoon Suk Yeol's attempt to decree martial law in December. The opposition Democratic Party largely opposes building nuclear weapons.

It's unclear where the new Trump administration stands on South Korea's prospective weapons development. Seoul's ambassador to the U.S. highlighted to reporters Wednesday that the new administration's diplomatic communications advocate only for "denuclearization of North Korea."

By contrast, the Biden administration's statements often called for the denuclearization of the entire Korean peninsula, the envoy added. (The White House, State Department and National Security Council did not immediately respond to comment requests from USA TODAY.)

Davis Winkie's role covering nuclear threats and national security at USA TODAY is supported by a partnership with Outrider Foundation and Journalism Funding Partners. Funders do not provide editorial input. If you wish to share a news tip, please contact Davis via email at dwinkie@usatoday.com or via the Signal encrypted messaging app at 770-539-3257.