It won’t affect the outcome. The complicit GOP is still going to acquit their crime boss. And even though it technically means the impeachment process was not “partisan,” I don’t expect the GOP to stop insisting it was.
The main effect will be to make the other gooper senators look like the shitty little weaklings they are.
I don’t think it was some triple-bank political calculation by Romney. I think he honestly believes he swore an oath, and he’s already eaten all the shit from that traitor criminal that he’s going to eat.