The issue is now before a Florida court as a civil suit, brought by a Muslim housewife, Sultanna Freeman and the state ACLU. Ms. Freeman wears a niqab, an Islamic veil that covers her entire head except for her eyes. Her religious beliefs dictate that she not reveal her face to strangers or men outside the family.

Though Florida says it wants to accommodate drivers from various cultures, it draws the line at ID photos that are, in effect, useless for identification. The state allowed a veiled photo when Ms. Freeman first applied for a license, before the terror attacks of Sept. 11. But now it wants her to pose for a full facial picture like all other drivers. In late June, a Florida judge ruled that Ms, Freeman could proceed with her suit against the state.

Robert Sanchez of Florida's department of highway safety and motor vehicles raised the common-sense objection to a veiled photo: Police need to know that the person presenting the photo is the person pictured on it. He adds that law enforcement often requires people to do things that offend modesty or religious principles, for instance, submitting to a strip search. Ms. Freeman's lawyers argue that 12 states do not require photos if religious objections are raised.

As a matter of public policy, Florida has a strong case. Having drivers' faces visible in license photos is an obvious issue of public safety, particularly after the events of 9/11. Presumably even the most diversity-minded public officials will have trouble coming out in favor of ID photos that leave faces almost totally obscured.

Imagine that a woman in front of you at an airport security check is wearing a veil. She presents as her legal ID a Florida license showing only her eyes. The airport security personnel have no way of knowing whether the license is actually hers, so they don't really know who she is. But out of cultural sensitivity, they wave her through anyway. Do you really want to fly on that plane?

Though Florida has a Religious Restoration Act that protects the rights of religious objectors, Ms. Freeman's argument is unlikely to prevail. In 1992 the U.S. Supreme Court tilted narrowly but decisively against exemptions. In a 5-4 decision in 1992, the court ruled against two men penalized for religious use of peyote. In effect, says constitutional scholar Arthur Eisenberg of the New York Civil Liberties Union, the court ruled that "except for laws directed exclusively or discriminatorily at religious beliefs and practices, free exercise (of religion) claims deserve no serious judicial consideration at all."

The following year, Congress passed the Religious Freedom Restoration Act, intending to trump the court. But the court had the last word, declaring the act unconstitutional and leaving the anti-exemption ruling in place.

A number of religion-based challenges to dress codes and safety rules are working their way through the courts. Should schools that maintain a zero-tolerance policy on weapons allow an exception for the ceremonial curved dagger that Sikh males, including schoolboys, must wear at all times? Many U.S. and Canadian schools quietly allow the daggers, but the province of Quebec has raised a legal challenge, citing 12-year-old Gurbaj Singh, who has worn his dagger since he was 5.

A court ruled that Singh could keep wearing it in school as long as it is securely enclosed in a wooden sheath, tied shut and worn under his shirt. But still, the dagger is a weapon brought to class every day, so Quebec is appealing the court decision.

In the United States, a challenge to the Sikh dagger in schools would immediately broaden into a church-state issue: by allowing a weapon because it is a religious symbol, schools would be preferring religion to non-religion, unless it allowed other weapons on grounds of conscientious but non-religious objections. If so, a challenge to the Sikh dagger could put all no-weapons school policies in jeopardy.

All diversity exemptions tend to sound benign, but many are highly questionable and headed for court.