Also note that they could also impeach Trump at any time. The sort of crimes that justify impeachment are pretty easily demonstrable at this point so all they need are the votes. They'll have just under half in the House and Senate from the Democrats, so they only need a handful of Rs in the House and (the hard part) a bit over 1/3rd of the Rs in the Senate.

So if they can find like 20 R senators who realize that they no longer support a Mad King, they're all set.