As one of a handfull of liberals who protested Saddam with Iranian expats (many who then went back and died in that war), there was no liberal or democratic opposition to thatsupport, and much of it was secret at the time. Nobody flipped. Not one. When they became aware of it later (Iran/Contra) and the first Iraq war ramped up, they were consistently against it.
Republicans haven't been isolationist since the 40s.
There is little, if any extreme change in D voters over the last several decades. There is no vice-versa, it's false equivalence nonsense.