There are several possibilities here. If Trump is charged and convicted with crimes connected with planning the January 6th insurrection, he would be legally ineligible to run for any government position. It is also possible he could be jailed for tax issues. I doubt this, because money. If he is not charged and convicted, he could run. He could easily get 40% of the Republican vote, which is all he needs to gain the nomination. From there, the GOP will line up behind him, and we could have a close election. Joe Biden could run for reelection, but I think he is simply too old. That is a hard job, and it takes a toll on anyone who cares about the job, plus he was old when he first got elected. So the Dems need a younger candidate. Kamila Harris hasn’t made friends while acting as Veep, and I doubt she can win on her own. I could easily vote for Amy Klobuchar.