South Korea’s president is digging in against a second impeachment vote in the national assembly, scheduled for Saturday.

President Yoon’s foes, looking for vengeance at last for his reckless attempt at stifling their opposition by imposing martial law, are expected to pick up the 200 votes needed for their impeachment motion to carry the 300-seat assembly.

That’s because the leader of Mr. Yoon’s People Power Party is telling its members to vote according to “conviction,” meaning a number of them won’t stand fast against impeachment, as almost all did in the first impeachment vote, last Saturday.

Seoul’s Yonhap News quoted the PPP leader, Han Dong-hoon, as saying “the president’s duties must be swiftly straightened out and suspended through the impeachment process.”

Mr. Yoon will “either be impeached or resign,” a retired Korean army general, Chun In-bum, told the Sun, ascribing Mr. Yoon’s troubles largely to opposition within his own party. “It’s not the differences between the PPP or the DP [Democratic Party] that is the issue,” he said in an email. “It’s the division within the PPP that will be the fall of the PPP,” referencing the failure of the PPP to unite firmly behind the president in the assembly.

“PPP leader Han Dong-hoon’s effort to arrange an ‘orderly exit’ for the president via resignation has failed,” a former senior American diplomat at Seoul, Evans Revere, told the Sun. Mr.  Han “appears to be on the verge of asking party members to support a second impeachment resolution. The national assembly opposition needs only a handful of PPP votes to ensure passage of the impeachment resolution, and there may be enough anti-Yoon sentiment in the party to produce the needed votes.”

Mr. Yoon, though, will not be out just because he’s impeached. As in the case of President Trump, twice impeached by the House of Representatives, impeachment needs a final seal of approval — in Trump’s case by the Senate, whose Republican majority quickly voted down the efforts.

In Korea, six of nine members of the constitutional court must approve the motion. However, unlike in the American system, in which the impeached president retains the power of his office, the Korean prime minister becomes acting president and keeps the post until a special election is held to determine the next president.

Korea’s prime minister, Han Duck Soo, a former ambassador to Washington who has said he opposed the martial law motion, is waiting in the wings while Mr. Yoon, bloodied but unbowed, is defending his ill-fated decision to impose martial law — a move that was quickly defeated by the strong Democratic Party, or Minju, majority in the assembly.

Although Mr. Yoon rescinded the decree six hours later, he believes passionately that he did the right thing. Martial law was an attempt “to protect the nation and normalize state affairs,” Yonhap quoted him as saying. “Whether I am impeached or investigated, I will fairly confront it.”

The Minju faces its own problems. Its leader, Lee Jae-myung, a former provincial governor and mayor of a city near Seoul, whom Mr. Yoon defeated by less than 1 percent of the votes in the 2022 election, faces charges of corruption in real estate and other scandals for which he is to stand trial.

Still, “Lee is the figurehead of the progressives/Left,” General Chun said. “He has proven himself as a capable administrator. He has the support of the radical left and as of now, their interests coincide with Lee.”

Although Mr. Yoon  may appear to have fumbled badly, he has ardent defenders who view the Minju’s attempts to tar him as a “traitor” guilty of an “insurrection” as a leftist plot influenced by China. Mr. Yoon’s defiance, though probably futile, means that Korea will remain sharply divided between the leftist-dominated Minju and the conservative PPP.

Meanwhile, Mr. Revere said, “The noose is tightening on President Yoon and those around him who sought to impose martial law. Prosecutors are building a case against Yoon that would charge him with rebellion — a very serious offense.”