I'm a historian, so I don't get so panicked at these "divides." Americans are ALWAYS divided. No, you didn't see a lot of partisanship in WW II by the GOP . . . but they did hold lots of hearings on "merchants of death." In 1940, Wilkie was buried electorally, but got quite a bit of the pop. vote. In the 1880s, we had almost THIRTY YEARS' worth of close elections, usually decided by a handful of midwestern states, and tensions were very high, esp. in the old Confederacy.
Thanks. Your perspective is interesting.