I know we have theorized about who that could be, but it's starting to look like it could be Joe Biden. The way the media is attacking him now, on all fronts, it seems like just a matter of time.
Once everything comes out, and it will now that the MSM is turning on him, people will be open to the idea that the election was stolen. That is why no one is talking about 2020 right now. It's not time for that can of worms to be opened. Soon, it will be.
Also, throw in the vax issues being exposed... It's heating up. Friday the 13th has been glorious. What was it about 11.3... Same as 1-13? The tide has turned, in a major way.
Nobody is sure. In fact the Justice Dept has a memo prohibiting them from indicting/arresting a sitting POTUS because it would break separation of powers between the branches. SCOTUS has never ruled on it. Political lawyers/professors disagree based on which team they play for.
Fact is, if a POTUS does something so illegal and egregious that a normal citizen would be arrested the Constitution provides for impeachment. If the POTUS were impeached and convicted they would be arrested - before another President took over and granted a full pardon like Ford did for Nixon.
Interesting theory though... Let's say Biden goes completely postal, grabs a gun from the Secret Service, and kills a few people in his office. There is no way he could be allowed to remain President, but an impeachment process takes a long time (comparatively).
I can think of an air-tight way to remove him pretty much immediately. There doesn't seem to be a prohibition on a POTUS being detained, so handcuff him and lock him in a room, have someone alert his Cabinet, and they would 100% 25th Amendment him. They would probably have to go to SCOTUS at that point for guidance because a timer starts limiting the amount of time the VP can take over. Reading the 25th (Section 4) it looks like it could take a minimum of a couple days before the process of removal can be finalized depending on Congress being in session and the Cabinet being able to meet - and to have the proper number of votes. POTUS obviously could not be detained that long without some precedent.
Even if the 25th lasted the maximum amount it is allowed it would still possibly be faster than an impeachment and a trial. Either way (25th and removal or Impeachment and removal) he would be arrested immediately after one of them was finalized. He would probably be under house arrest until then.