Italian Catholics were republican in nyc
This is my guess. Though they were not particularly different in beliefs, NYC Catholics were more likely to be Republicans because men like Fiorello LaGuardia, John Marchi, and Paul Fino (and maybe even Vito Marcantonio) had brought many Italians into the party.
I'm guessing Irish Catholics were more Democratic in Boston than in other cities (maybe excluding NYC) because the local Democratic Party was so heavily influenced by Irish leadership.
I'm pretty sure all white ethnic groups were more democratic in New England. The primary conflict there tended to white ethnics vs white WASP so there was less divisions between white ethnics.
