To what extent is religious liberty reducible to the rights of conscience? That is one of the questions Brian Leiter's new book, Why Tolerate Religion?, tries to answer. It's a question that's been on my mind again since the Department of Health and Human Services announced its new proposal for accommodating nonprofit religious organizations, such as hospitals and universities, but not private employers, such as the Hobby Lobby.

The distinction makes sense to me, even if in this particular case it might not have been hard to accommodate any employer who didn't want to pay for contraceptives. As Eduardo Pealver suggested in his Friday post, if a health-insurance company actually saves money by covering contraceptive services for its policyholders, then the Obama administration may as well have required insurance companies to offer free contraceptive coverage to those employed by any business owner who objects to paying for it—and thereby avoided all the political problems that have arisen from the HHS mandate.

While the HHS's decision to distinguish between religious nonprofit employers and for-profit employers who happen to be religious makes sense to me, it seems perfectly arbitrary to many conservatives, including many Catholics. Why privilege the religious liberty of a hospital or university, they ask, and not that of a small-business owner who is also a devout Catholic? What does it matter whether the organization's primary mission is religious or secular? And why should the integrity of an institution count for more than the conscience of an individual?

I don't pretend to have perfect answers to all these questions. But the line taken by some champions of religious freedom, such as the Becket Fund, seems to me untenable. It would logically lead to a situation they couldn't possibly wish for. Should an overzealous Jehovah's Witness be able to get a group plan that excludes coverage for emergency blood transfusions, even if none of his employees are coreligionists?

But that is a hard case, you may say, and hard cases make bad law. How many other religious believers object to health services that most people consider morally unproblematic? Well, a few: there are the Scientologists, with their extreme skepticism of psychopharmacology; there are unreconstructed Christian Scientists—now in decline but once a very prominent sect—with their general suspicion of drugs. (I have a distant relative who died because of that suspicion.)

But why even restrict this to religious believers? What if someone believes, as a matter of conscience unrelated to any religious conviction, that it is immoral to avail oneself of a medical treatment that was ever tested on animals? Should such a person be able to line-item-veto insurance coverage for dozens of treatments in the health plan available to his employees? Where would this end?

(Perhaps you think that, while this problem is theoretically interesting, it's unlikely to present any practical difficulties, since an employer with such an idiosyncratic view of health care would in any event be unlikely to find a policy that answered to his requirements, the market for such a policy being prohibitively small. Maybe, maybe not. With lax enough regulation, it's possible to imagine an la carte market for health insurance, each plan or policy tailored to the whims of the customer and priced accordingly. I'm not an expert on the insurance market, but I think it's fair to say that, as a general rule, some insurance companies will sell any old crap if regulators let them get away with it.)

But now imagine a militant atheist who is convinced by the natural-law argument that contraception is gravely immoral. (I realize this example may appear to require rare powers of imagination, but bear with me.) He owns a business, too, and wants an exemption from the contraception-coverage mandate. Should the fact that his belief is not attributable to any faith matter? After all, he believes that contraception is wrong for precisely the same reason the Catholic Church teaches that it's wrong, even if he doesn't accept the Church's authority to teach anything. Someone might reply: I can just about imagine such a person, but he must be one of kind, or at most one of a few. But if you can imagine this small business owner, you can also imagine one who believes, for reasons moral but not religious, that prostheses of any kind are an affront to the dignity of the human body, and another who believes that neonatal intensive care units are a waste of precious medical resources on nonpersons and so refuses to pay for an insurance policy that would cover an employee's prematuraly born child.

Leiter believes claims of conscience should be accommodated if they do not threaten someone else's individual rights or an important public interest. But he also believes they should not be understood to have any extra force—or to warrant any special deference—just because they originate from religious faith. A conscientious objector, for example, should not need to prove he's a Quaker. Or, to take a recent case from Canada that Leiter mentions in his book, if you allow a student to carry a ceremonial dagger to school because he's a Sikh, you should allow another student to carry a knife because he sincerely believes, in accordance with his rural upbringing, that carrying a knife is a sign of honor and manhood.

I disagree with Leiter about some things, including his low esteem for religion and religious institutions in general, which he regards as seedbeds of irrationality. Unlike Leiter, and like many conservatives critics of the original HHS mandate, I think the federal government has good reason to give churches and other religious organizations broad latitude, and that this reason has something to do with the important and unique role religious institutions have played in our nation's history. But when it comes to individuals who object to neutral laws of general applicability, I'm not at all sure why the government should discriminate between sincere religious belief and any other kind of sincere conviction.