In the comments to the post about the Muslim policewoman who was barred from wearing a khimar on the job, one of the commenters expressed regret that the decision "means that observant Muslim women are, in effect, barred from serving as police officers." Another commenter responded,

Considering the restrictions most Muslim countries place on women I'm surprised that she thinks she can be a police officer in the first place, in a country that expects women cops to drive, handle guns, arrest men, etc., just like the male ones. (Saudi Arabia does have women on the police force, but AFAIK they really function as a sort of auxiliary so male cops don't have to manhandle, search, or even talk to non-related women.) OTOH, if she can be flexible about those restrictions, why can't she be flexible about the head-dress? The department isn't requiring that she go bareheaded, just that she wear the uniform hat. As I understand it, Mohammad only prescribed that women be "modest"; interpreting that as any particular garment is a cultural thing, not Islam.

I've heard similar arguments before, but they've always struck me as quite weak, a weakness that we can see if we adapt them to Judaism or Christianity. We know how varied Judaism is -- yet we don't express surprise when, say, a Reform Jewish man refuses to eat pork but doesn't wear a yarmulke. Nor would we, I think, have prisons deny Jewish prisoners pork-free meals just because the prisoners aren't full-on Orthodox, on the grounds that "they're flexible about some Orthodox Jewish religious laws, why can't they be flexible about pork?"

Likewise, some Christians observe a Saturday Sabbath; some observe a Sunday Sabbath; some observe no Sabbath (in the sense of a day of rest) at all. Many Christians are very serious about following some Old Testament rules, but think the others (such as the Sabbath observance and the kosher rules) have been superseded. Why isn't it equally plausible that some Muslims may interpret Islam to allow women a great deal more latitude than the Wahhabi do, yet still preserve some aspects of traditional Islamic women's garb?

Similarly, it's not uncommon for cultural rules and religious obligations to be closely intertwined. As I understand it, the requirement of wearing a yarmulke is a cultural tradition that is not understood even by the Orthodox as being mandated by the Torah. I'm not sure about this, but my sense is that the wearing of Christian-themed jewelry and the placement of ashes on the forehead on Ash Wednesday is "cultural" in the sense of not being seen as mandated by religion, but is surely linked to religious sentiments.

It may well be that the court's decision in this case is right; I'm not speaking about that here. My point is simply that some American Muslims' rights shouldn't be determined based on what Saudi Muslims do, or even other American Muslims do, just as some American Christians' rights aren't determined based on what other Christians do, and some American Jews' rights aren't determined based on what other Jews do.

Islam, Christianity, and Judaism all include multiple denominations, both formal and informal. And American religious freedom law recognizes that no religion ought to be treated as a monolith with a single Established Official View that somehow affects the rights of all members of that religion.