Did you miss the news? The president has "absolute presumed immunity for 'official' acts".
Just like the good ol' days ~/s~ where insane kings wage wars, massacres, and massive destruction.
Edit: But even assuming before 2025, when we still had the rule of law, it's up to the vice president + a majority of the cabinet to, via the 25th amendment, declare the president "unable to discharge the powers and duties of his office", and then congress has 21 days to vote, via 2/3 supermajority in both houses, to finalize it and makes the VP, permanent Acting President.
Normal impeachment is easier, only takes 1/2+1 of the house and doesn't require the VP's cooperation, this convoluted "inability" clause is even harder to invoke.
Also, the then you'd have an insane Acting President, so problem isn't really solved.
TaiShan 1989? Nothing happened there.