South Korea, one of Washington’s closest allies in East Asia, is no stranger to scandal and political intrigue. But the last two weeks of political infighting in Seoul has made the previous 40 years look like a snooze-fest by comparison.

The latest saga started Dec. 3, when South Korean President Yoon Suk Yeol inexplicably declared martial law in response to what he claimed was an opposition-run National Assembly that was trying to stop the machinery of government, impeach his officials and block his agenda. It was the first time such an extreme measure was used since South Korea transitioned into a democracy in 1987. Shortly thereafter, hundreds of South Korean troops and police officers descended on the National Assembly, blocking lawmakers from getting into the facility and even coming to blows with staff.

Yoon’s decree, however, didn’t last long. Hours later, lawmakers inside the assembly building voted to overturn martial law. The troops pulled back, and Yoon was forced to give a speech apologizing for the harm his decision caused. Yoon’s political career is essentially over. On Saturday, the National Assembly impeached him on a 204-85 vote, with 12 members of his own party joining the effort. (His powers are suspended until the Constitutional Court makes a verdict on whether the impeachment stands.)

Worse still, Yoon is now under investigation for rebellion and is barred from leaving South Korea. A man who made a name for himself as a prosecutor may become the face of criminal malfeasance.

For the United States, this entire affair is not only embarrassing but potentially disruptive to our geopolitical agenda in East Asia.

It’s embarrassing because President Joe Biden’s administration frequently held up South Korea as the beacon of democracy in Asia, the quintessential success story of a military-run autocracy-turned-pluralistic society. To state the obvious, having a democratically elected president turn into a wannabe dictator, where dissent is stifled and parliament is turned into a relic, isn’t what Washington expected.

“I think President Yoon badly misjudged,” Deputy Secretary of State Kurt Campbell said days after martial law was rescinded. “And I think the memory of previous experiences of martial law have a deep and negative resonance in South Korea.”

Yet even more important than the optics is how the saga in Seoul could bleed into U.S. policy plans in this region. At first glance, it looks like a domestic South Korean affair. In many ways, that’s true; nobody is calling for the Americans to ride into Seoul as a mediator, particularly when its own democracy isn’t exactly characterized by compromise at the moment.

The U.S. foreign policy establishment, though, has reason to worry about what Yoon’s demise as a leader might mean for its broader grand strategy in Asia. Yoon may have been a depreciated commodity in the South Korean capital, but he was feted in Washington as a visionary. Yoon, for instance, used a significant amount of political capital to improve South Korea’s relationship with Japan, another key U.S. ally in the region but one whose historical differences with Seoul over the 1910-45 Japanese occupation of the Korean Peninsula hurt Washington’s ability to create a latticework of alliances to contain China and North Korea.

Unlike his predecessor Moon Jae-in, Yoon was willing to stick his neck out for the sake of better ties between Seoul and Tokyo. To many South Korean presidents, Japan’s occupation of Korea was something that couldn’t be forgotten; for Yoon, it needed to be put into the history books to deal with the here and now.

Biden couldn’t have been more thrilled. Yoon’s willingness to move past this historical baggage meant Biden could pursue his East Asia strategy, which rested on stronger trilateral ties among the United States, South Korea and Japan. In August 2023, Biden, Yoon and then-Japanese Prime Minister Fumio Kishida announced a comprehensive aspirational agreement that would institutionalize relations between their countries on all matters of mutual interest. Trilateral military exercises in the air, on land and in the sea became routine, South Korea and Japan were sharing more intelligence with each other on North Korea’s missile program, and the two countries were following Washington’s line on Taiwan more frequently.

Yoon’s potential departure from office, however, risks undoing some of that progress from Washington’s perspective. Assuming Yoon’s impeachment stands, South Koreans will go to the polls in 60 days for another election. The favorite, opposition leader Lee Jae-myung, is a traditional South Korean leftist who views Japan skeptically and doesn’t believe South Korea’s foreign policy should mirror Washington’s own. Indeed, Lee has referred to Japan as a “hostile state.” In October 2022, the opposition politician even suggested that trilateral military drills with Japan could eventually result in Japanese forces raising its flag again on the Korean Peninsula.

Lee’s views on China don’t jibe with Washington’s, either. Although Yoon was never a China hawk, he was willing to call out Beijing for transgressions when he thought it was necessary. It’s difficult to see Lee as president doing this because he wants to rebuild relations with China and doesn’t believe putting all of South Korea’s eggs in America’s basket is a sound strategic move for a middle power. On Taiwan, a subject U.S. foreign policy analysts are obsessed with these days, Lee is unequivocally detached. “Why do we interfere in cross-strait relations?” he asked earlier this year. “Why do we care what happens to the Taiwan Strait? Shouldn’t we just take care of ourselves?”

Ultimately, Yoon was more popular in Washington than he was in Seoul. His departure as leader will create questions for the U.S.-South Korea relationship.

Daniel DePetris is a fellow at Defense Priorities and a foreign affairs columnist for the Chicago Tribune.