I recently came across Clayton Christensen's recent article in the Washington Post: A Theist Balance on the Court.
I liked the pun on a-theist.
But, more seriously, I think that the topic of "voluntary obedience to unenforceable laws" is core to the American experiment.
There is a point at which people cannot be governed by law except to their own detriment. I believe that this point is reached when individuals decide to trample each others' rights and attempt to defend themselves, by legal or illegal means, in doing so.
And I very much like Clayton's reframing of the problem: If the "religions of atheism and secularism offer us no institutions whose mission is to inculcate in the next generation of Americans the instinct to obey unenforceable laws," then it is improper to marginalize the contribution of any and all of the institutions that DO inculcate such an instinct.