Julian Sanchez on the assertion that morals require a religious foundation:

…insofar as it tacitly makes a claim about people’s incentive to behave morally, it amounts to an admission that the speaker simply cannot fathom why someone would treat others with consideration and respect (if it didn’t seem to be in their self interest to do so) absent an omniscient being brandishing a heavenly carrot and the stick of damnation.

Indeed. When someone says, “Well, I’m sure I wouldn’t be able to maintain ____ if I didn’t have a foundational belief in God,” I think, Well, it seems to me that would be a moral failure on your part. It communicates more about you and your moral imagination than about the world or the foundations of morality.