That's where it's a fun crisis. His VP was the sewer socialist mayor of Milwaukee and would have made a great president, but that'd mean they let a proper socialist hold the office. If they ratfuck him to install someone further down the line of succession it's a precedent and a massive radicalising point which shows how farcical bourgeois democracy is. If they release him from prison he's a king, if they don't he's a martyr. All the options hurt the system. Reactionaries have that same set of conditions set up for them with Trump.