Not to jump the gun (or the shark), but asking whether a convicted felon (federal or state) can be president no longer falls in the category of fantasy/science fiction. Experts on election law are starting to wade in on the question. UCLA law professor Rick Hasen noted "The Constitution has very few requirements to serve as President, such as being at least 35 years of age. It does not bar anyone indicted, or convicted, or even serving jail time, from running as president and winning the presidency." So, the baseline is "Yes, Donald Trump can definitely run for president, even in prison" (as did Eugene Debs in 1920 and Lyndon LaRouche in 1992).
Serving is a bit more complicated (aside from the logistics). Legal experts have noted the third section of the Fourteenth Amendment, which reads:
No person shall be a Senator or Representative in Congress, or elector of President and Vice President, or hold any office, civil or military, under the United States, or under any State, who, having previously taken an oath, as a member of Congress, or as an officer of the United States, or as a member of any State legislature, or as an executive or judicial officer of any State, to support the Constitution of the United States, shall have engaged in insurrection or rebellion against the same, or given aid or comfort to the enemies thereof. But Congress may, by a vote of two-thirds of each House, remove such disability.
If Trump is convicted only of falsifying business records, he's home free. That is also true if he is additionally convicted of storing classified documents in his bathroom. A conviction on the federal indictment about conspiring to defraud the United States gets close to nailing Trump for engaging in an insurrection and the Georgia RICO case gets even closer. But in the end, where does the rubber hit the road? The Amendment is not self-enforcing. The most likely case where this could play out is one in which the secretary of state in some state refuses to put Trump's name on the ballot on account of #14.3. SCOTUS would then have to make the call.
Another way this could play out is Trump's already-underway attempt to move the Georgia case to federal court. If that succeeds, then at worst he could be convicted of a federal crime and a Republican president could try to pardon him for it. If Trump were to issue a pardon for himself, could someone sue to have the pardon invalidated? Who would have standing to sue in that case? These are good questions.
Additionally, since the Georgia RICO law is broader than the federal one, Fulton County DA Fani Willis will argue that moving the case to a court where one of the charges (forgery) is not an allowed crime for RICO would be letting Trump get away with it for no reason. We doubt the move will succeed for that reason. Also, he is accused of violating a Georgia law, not a federal law, so why shouldn't the case be tried in a Georgia state court?
Another aspect of all this is a new law Gov. Brian Kemp (R-GA) signed in May. It established a commission that has the authority to remove D.A.s who are not doing their jobs. Trump is certain to ask some friendly Georgia resident to file a complaint asking for Willis to be fired. It is unlikely to succeed, but if it does, Kemp has the power to name a replacement D.A. Kemp is not a big Trump fan and would probably name one of Willis' deputies to continue the case.
There are no doubt all kinds of weird issues that are going to come up in the next year as Trump doesn't really like being president but he really, really, really, does not want to go to prison, so he will try every Hail Mary play he can think of. The place where it gets really hairy is if Trump is convicted on either or both federal counts or the Georgia one after he has enough bound delegates to win the nomination. What will RNC Chairwoman Ronna Romney McDaniel do? Unbind the delegates? But since they are Trump delegates, they might still vote for him at the convention. Then what? (V)