Until you post a source for how northern Catholics and Northern Protestants vote it will be pretty hard to figure out what you are trying to say.
The Hispanic vote is very clear.
The Protestant vs. Catholic vote up there is fairly clear. Having lived up there for so many years, it is fairly evident in every day life, too.
Here is a link from 2008.
http://www.cnn.com/ELECTION/2008/results/polls/#CTP00p1
The 2004 cnn exit polls have more state results that are divided by religion. Connecticut, Massachusetts and New York have similar results to these 2008 Connecticut numbers at the link below. Vermont and some other states don't follow this trend at all. The only speculation I could make is that the states with the highest Irish and Italian Catholic populations had more conservative Catholic voting behavior. The 60-65% Democrat vote for Protestants in these states I can't explain.