The US Constitution does not prevent a convicted felon from running for President, even if they're imprisoned.

This probably bugs most anti-Trumpers.

But I think it's appropriate. It really would be dangerous if one party's leaders - whether at the state or federal level - could gin up charges, get lucky with a hostile jury, and so prevent an electoral challenge from a tough opponent.

Impeachment remains on the table, were Trump to regain the presidency, but short of that high bar, the proper judges as to fitness of a candidate are the people.

That the majority of the people (both pro- and anti-Trump) are utterly unqualified to participate in leadership selection is irrelevant. It is better to let them judge than a handful of jurors (who ought to be given neither the opportunity nor the burden of determining a prospective candidate's future political opportunity).

The blunt reality of popular government is that you always risk having a horrible person selected to office. It's still a better system than non-popular government, which virtually guarantees you'll get a horrible person in office.