Religious identity doesn't make much of a difference when it comes to voting in New Hampshire, as demonstrated by a new poll conducted by JZ Analytics for the Washington Times. It shows the two Catholic candidates, Rick Santorum and Newt Gingrich, actually doing worse with Catholics than they do with Protestants. And Mitt Romney does just about as well with GOP primary voters who identify themselves as born again--evangelicals, mostly, one presumes--as he does with everybody else.
As Andrew Walsh and I argue in One Nation, Divisible: How Religion Religious Differences Shape American Politics (just out in paper, with new material on the Obama presidency), New Englanders embraced a principle of church-politics separation in the mid-20th century in order to put the grim Yankee-Irish Catholic conflicts of the previous century behind them. John F. Kennedy brought that principle to national politics when he won the presidency in 1960. And it's why New England pols like Michael Dukakis, John Kerry, and Howard Dean tend to handle religion so badly on the national stump.
That's not to say that religion doesn't matter at all in New England, but you have to look carefully. In the JZ Analytics poll, Santorum, at 10.8 percent overall, does do a good bit better with the born-agains (19.7 percent) and those who attend worship services once a week or more (21 percent). That's an opportunity for him, but a small one. There aren't a lot of born-agains in New Hampshire, and these days (according to our 2008 ARIS survey), northern New England is the least religiously affiliated region of the country. survey), northern New England is the least religiously affiliated region of the country.