When Clinton was impeached it was the first time on a 6th year election in 160 years that the presidents’ party gained more seats than the opposition.

Wouldn’t similarly the likely fallout be:
1) It energizes the Republicans who will be angry about it
2) It discourages the Left who thought that impeachment implies removal

I can’t imagine in any world that even one vote will swing from right to left just because he got impeached.

He would pretty much be guaranteed election, and could also get back the house as a result.