MacDonald is talking good sense when she says that conservatives should be able to agree on policy without agreeing on theology. I’d want to know a little bit more about what she considers “natural law” to mean before signing on to her dismissal of it.
Where I think she goes empirically astray is with this passage: “[T]he conservative movement is crippling itself by leaning too heavily on religion to the exclusion of these temperamentally compatible allies. Conservative atheists and agnostics . . . . view marriage between a man and a woman as the surest way to raise stable, law-abiding children.”
I take this passage to express opposition to same-sex marriage. Let us leave aside two questions here in evaluating MacDonald’s claim. The first question to ignore is whether opposition to same-sex marriage should be a central conservative cause. The second is whether valid and decisive rational, non-religious arguments against same-sex marriage exist. Is it true that the conservative movement has been “crippling itself” by alienating atheists and agnostics who oppose same-sex marriage? How many such people are there, and how alienated are they? My guess is that there are only a handful of non-religious people who object to same-sex marriage, and that the few people who hold that set of views will almost always be willing to work with conservatives who, to coin a phrase, agree with them on policy while disagreeing on theology.
Incidentally, MacDonald’s piece is a contribution to a symposium. I’ve read a little more than half of it. So far, the best contributions are by Austin Bramwell, Ross Douthat, and Michael Lind. (I’d link but for technical difficulties: They’re all at amconmag.com.)