Impeached and accused of insurrection, South Korea’s president is fighting to cling to his post in the face of mass protests calling for him to quit immediately.

Stonewalling to the end, President Yoon has ordered his security people to close the doors to attempts to find incriminating documents while refusing to show up for questioning by multiple teams of investigators.

In his latest rebuff of investigators, Mr. Yoon on Wednesday ignored a demand from the Corruption Investigation Office, separate from the police and prosecutors, to answer its summons. An aide said he would “comply with the investigation” but added that Mr. Yoon did not “consider the charges to be legally valid.”

The failure to cooperate with the investigation despite passage of an impeachment motion last Saturday by the national assembly ushers in what looks like the climactic phase of the effort to oust him from office completely.

Although Mr, Yoon still has the title of president, the authority of the office automatically devolved to the prime minister, Han Duck-soo, from the moment on December 14 when the assembly speaker announced that 204 of the assembly’s 300 members had voted for impeachment. With Mr. Han ensconced as acting president, the country’s constitutional court begins on December 27 consideration of whether to approve the impeachment motion.

Mr. Yoon’s intransigence against investigation of charges that he fomented an “insurrection” by ordering martial law on the night of December 3 is evidently designed to prolong if not impede the case against him as long as possible. Having rescinded his martial decree six hours later after the assembly rejected it, Mr. Yoon now is paying the price for his ill-fated attempt at stifling assembly opposition.

The court has six months from the date of Mr. Yoon’s impeachment to come up with a ruling but is expected to act sooner — perhaps within two or three months. The court’s deliberations, though, are complicated by concerns that only six of its nine seats are filled. It takes six of the nine to vote in favor of an impeachment motion for it to be approved. 

Whether all six of the sitting judges would vote “yes” to impeachment is far from clear, especially as two of the judges were appointed by Mr. Yoon. His foes in the Minju, or Democratic Party, which controls a majority in the assembly, are demanding the right to name at least two more judges to the court.

The president — or in this case the acting president — must approve the appointments as voted by the assembly or else name nominees for the assembly to vote on.  Either way, a tremendous battle over filling out the court with judges who would be sure to favor Mr. Yoon’s impeachment appears inevitable.

In the low teens in popularity polls and bereft of presidential power, Mr. Yoon still commands the loyalty of aides willing to do his bidding in order to frustrate the  investigation. A team of investigators waited in vain outside the presidential office for most of the day Tuesday while the presidential security service refused to open up for a search.

“The raid targeted the security service’s computer servers,” Korea’s Yonhap News said. “The security officials are believed to be denying entry citing law on the protection of classified information.” Earlier, investigators had been rejected in attempts to obtain Mr. Yoon’s records and those of leaders of the armed forces.

Beyond the immediate investigation, the case is beginning to take on some of the tones of the demise of a previous conservative president, Park Geun-hye, in 2017. Impeached, ousted, and jailed, she was said to have been in the thrall of a woman with the mystical power of a shaman.

Prosecutors have arrested  a shaman on charges of receiving “illegal political funds”  laundered through a crypto currency fund named Queen Bee, according to Yonhap. He’s said to have been “flaunting his personal ties” to both Mr. Yoon and his wife, Kim Keon-hee, herself a controversial figure accused, among other things, of accepting a Dior handbag as a form of bribery.