I think he would've done similarly to Barnes.
If he had won in 2016 and everything had turned out the same, he probably would’ve won by around the margin Evers did (Johnson probably wouldn’t have been his opponent.) If he had run despite losing in 2016, I think the race would’ve ended up similarly to how it actually did.
Might've done slightly better than Barnes but I think Johnson would've still pulled it out. Could've been almost exactly 50-50 with Feingold.
If Feingold was the incumbent, he probably would’ve won re-election. If he was Ron Johnson’s challenger, he probably would’ve narrowly lost (similar margin to Barnes).
As a side note: Russ Feingold probably would be in the Senate today had he run in 2012 for the open seat. I imagine Tammy Baldwin wouldn’t have run in that case, and I think Feingold would’ve defeated Tommy Thompson. Given that Feingold wanted to return to the Senate after his 2010 defeat, it’s somewhat odd he waited to run till 2016 instead of running in 2012.
If Feingold was the incumbent, he probably would’ve won re-election. If he was Ron Johnson’s challenger, he probably would’ve narrowly lost (similar margin to Barnes).
As a side note: Russ Feingold probably would be in the Senate today had he run in 2012 for the open seat. I imagine Tammy Baldwin wouldn’t have run in that case, and I think Feingold would’ve defeated Tommy Thompson. Given that Feingold wanted to return to the Senate after his 2010 defeat, it’s somewhat odd he waited to run till 2016 instead of running in 2012.
Feingold probably would have won simply because national Democrats wouldn't have abandoned the race. Barnes nearly won even with that.
It would not have been a GOP pickup if there were a Democratic incumbent; the Republican nominee would've been someone significantly weaker than Ron Johnson, unfortunately.
If Johnson was the incumbent, and Feingold ran instead of Barnes in our world? I don't think it would've been any different.
Feingold would have probably been a MUCH weaker candidate than Barnes because he was a two-time loser.