My South Korean parents and I have a great relationship. They have embraced my same-sex marriage — an unusually progressive attitude in our country — and join my husband and me on trips. We can openly discuss just about anything.

Except Korean politics.

They are convinced that Yoon Suk Yeol, South Korea’s conservative former president, did the right thing in December when, while in office, he tried to impose martial law and arrest opposition politicians. His move threw the nation into crisis, another chapter in the intense and often pointless political antagonism that has engulfed the country in recent years.

When I called my parents the day after Mr. Yoon’s failed attempt, that irreconcilable national divide was evident even in my otherwise harmonious family: I condemned the blatantly undemocratic power grab, which revived grim memories of past military rule; my father praised it as necessary to rein in the opposition, which he views as pro-North Korea.

Mr. Yoon’s half-baked plot fizzled within hours. He was swiftly impeached and suspended from office. A ruling on Friday by the nation’s Constitutional Court made his removal permanent.

The failure of Mr. Yoon’s bizarre scheme has been hailed in South Korea and abroad as a triumph for democracy. There is nothing to celebrate here. South Korea is as divided as ever, and the whole affair should stand as a stark warning for democracies everywhere about what happens when political polarization spirals out of control.

South Korean politics has long been plagued by a deep rift that stems largely from the decades-long division of the Korean Peninsula between North and South. This split South Koreans into two opposing political camps — an anti-Communist one led by an authoritarian elite that favors a hard line against North Korea, and a leftist, pro-democracy camp that advocates working toward reconciliation with Pyongyang.