There's some weird argument by his cult that it's not in the constitution that a president can't be in prison. It's a lot of mental gymnastics, ignoring the fact that he traitorously stole classified nuclear documents from the US government, along with subverting democracy in the RICO case with the 18 co-conspirators.
You're conflating two things here. There is absolutely nothing in the cotus that bars someone from becoming POTUS because they are in jail. Imo, there should not be, just like you should not lose your right to vote simply for being a felon.
However, there is something in the cotus that bard someone from being an officer of the state if they've been part of an insurrection. This, imo, should bar him, but I'm curious to see how the court cases play out.
Treason is defined in the cotus, and none of the three things you posted would rise to the level of treason. The article even talks about it. Neither the Rico charges nor the classified documents, even with a conviction, would bar him from the presidency, but the jab 6th could make him ineligible.
Don't get me wrong, it should be disqualifying for any potential voter. . . but unless I'm missing something, this is certainly not treason and I don't know how it would disqualifying some other way.
Treason against the United States, shall consist only in levying War against them, or in adhering to their Enemies, giving them Aid and Comfort. No Person shall be convicted of Treason unless on the testimony of two Witnesses to the same overt Act, or on Confession in open Court.
As we are not in declared or open war with Russia, it doesn't fall under the definition of treason. If "an adversary" would rise to the level of "enemy" then that would allow the state to broadly interpret the law to encompass plenty of actions as treason, as "aid and comfort" is so vague. And this is the opposite of the intent of the founding fathers, as they specifically define it to both show how important it is and to stop the abuse of it by the state, which they had seen plenty of times.
Technically speaking, yes. Trump could be sent to prison tomorrow and still be elected President. There isn't any "the President can't be currently incarcerated" requirement. (Likely because the founding fathers thought it was self evident that a criminal shouldn't be elected President.)
As for how it would work, nobody knows. It's never happened. Would he get to go to the White House for 4 years and then have to return to prison to serve the rest of his sentence? (Assuming here that he couldn't just pardon himself.) Would he need to conduct presidential business from the Square Cell instead of the Oval Office? Would a SCIF need to be set up in the prison so that Trump could review classified materials from his cell?
We would be in totally uncharted territory if this happened.