PGSInfinity,
“I can’t help but wonder if America’s political divide springs from her immigration divide. Perhaps the redder areas were settled by America’s earlier, braver immigrants with the latter-day arrivals settling in the big cities. The latter ones would’ve been more timid, more herdlike, less likely to rock the boat…”

Most of the red states, and red portions of blue states, were settled by Scots-Irish (=Ulstermen). See Fischer’s “Albion’s Seed” for differences in poltical and cultural outlooks between the immigrants from North Britain (Ulster, lowland Scotland, Northumberland) and those who were Puritans or Quakers from southern England.