By "the trifecta", I mean the Presidency and (caucus) majorities in the House and Senate.
I supplied some examples for those who fear Democratic tyranny, but please feel encouraged to add any policies you think are likely.
When the question closes, I will create a poll with all the options (down to whatever limit there is on polls) from this question and give it another week to run, then resolve based on the results of the poll to the greatest precision available. (E.g., if I can make each option pay off according to its poll percentage, I will.)
Sorry it took me a while, but here is the followup poll to resolve this: https://manifold.markets/ijk1/what-would-democrats-would-do-if-th?r=aWprMQ
Rationale for these slightly weird criteria:
I think it's generally agreed that adding any justices, or impeaching and replacing a justice for political reasons, is an attempt at packing the court; but Clarence Thomas's open corruption means there's a strong non-political case for impeaching him, and replacing only one justice would not reverse the direction of the court, so impeaching him alone would not be enough.
@MarioFSchlitzer this is not clear. Please be specific about a concrete policy or real-world outcome that can be bet on.