This is an odd bit of political trivia but enough of the states which Trump won his electoral votes from have laws forbidding Felons from taking office. If the democratic party just sues in those state, they could revoke enough electoral votes to prevent Trump from getting his second term.

It just requires them to enforce the laws that already exist. The only counter the Republicans have is to repeal the laws preventing felons from holding office. (Some of them started to realize this https://www.latintimes.com/republican-bill-inspired-trump-would-let-convicted-felons-run-public-office-missouri-568981)