An indictment of Trump on phony charges will come at some point. They can't back off now. If you attack the king, you better kill him.
The DOJ is just deciding on whether to do it before the midterms or after. If they do it before, will it piss off Republicans and make the "red wave" bigger, or will it demoralize them? Will it give Dems something to cheer on and embolden them?
The GOP will not take it lightly.
The immediate repercussions would be the whole republican party laying down and showing their bellies.