Chuds would either do a Rittenhouse and make them a hero, or would claim its some deep state pysop to both make them look worse and install the real communist leader.

As for what would happen, I don't know the line of succession there, assuming they hadn't actually said the oath then trump would remain president until the end of the day, then Pelosi would be acting president until the next person is chosen, Im not sure how that's decided but I imagine dems will just pick someone credible rather than hold another primary