A lot of people ask whether fusionism — libertarians and social conservatives joined in a political movement — makes sense. It does, and there’s a behavioral/sociological basis to it that Michael Gerson alludes to in his review of Robert Putnam’s new book:
At a recent conference of journalists organized by the Pew Forum on Religion and Public Life, Putnam outlined the conclusions of "American Grace," based on research still being sifted and refined. Against the expectations of hard-core secularists, Putnam asserts, "religious Americans are nicer, happier and better citizens." They are more generous with their time and money, not only in giving to religious causes but to secular ones. They join more voluntary associations, attend more public meetings, even let people cut in line in front of them more readily. Religious Americans are three to four times more socially engaged than the unaffiliated. Ned Flanders is a better neighbor.
It doesn’t stop there. Religious poeple live longer. Married people live longer too and make more money. I am not arguing causality, but co-occurence, which is all you need in a lot of political contexts.
Basically, religious people, on average, live lives more compatible with a libertarian economy message and system than others. Note the directionality on this. If a libertarian views their economic message (that is, they are what Europeans call "right-liberals", versus "left-liberals" who focus on social freedoms), then their most fertile ground for builing coalitions is with church-goers.
Thus fusionism.