Most likely, Joe Manchin would not become a full-on Republican, but being a Democrat, identified more and more with the Democrat-Socialist faction, is not tolerable much longer.
Look for some “Independent” label to be put out there.
Manchin wants to run for president. He in the past (maybe still does !) thinks his best path is as a Rat. I don’t see how he can think that its a delusion that he has a shot at it anyway as a Rat or anything else.
He should pull a James Jeffords (used to be a senator from Vermont, had Bernie’s current seat!) and go indenpendent but caucus with the GOP.
Anyway let’s see if his Prez dream dies and he makes a move.