Illustrating an intellectual confusion common on campuses, Vanderbilt University says: To ensure "diversity of thought and opinion" we require certain student groups, including five religious ones, to conform to the university's policy that forbids the groups from protecting their characteristics that contribute to diversity.

Last year, after a Christian fraternity allegedly expelled a gay undergraduate because of his sexual practices, Vanderbilt redoubled its efforts to make the more than 300 student organizations comply with its "long-standing nondiscrimination policy." That policy, says a university official, does not allow the Christian Legal Society "to preclude someone from a leadership position based on religious belief." So an organization formed to express religious beliefs, including the belief that homosexual activity is biblically forbidden, is itself effectively forbidden. There is much pertinent history.

In 1995, the Supreme Court upheld the right of the private group that organized Boston's St. Patrick's Day parade to bar participation by a group of Irish-American gays, lesbians and bisexuals eager to express pride in their sexual orientations. The court said the parade was an expressive event, so the First Amendment protected it from being compelled by state anti-discrimination law to transmit an ideological message its organizers did not wish to express.