The government provides vast subsidies to expressive associations. Universities and cities let groups use government property. Universities fund student groups' meetings and publications. The federal and state governments provide tax exemptions, which are tantamount to a matching grant. Many of these programs are available to a broad range of groups that meet certain objective criteria (e.g., student groups, nonprofit groups, and veterans' groups).

May the government limit these programs to groups that don't discriminate based on religion, sexual orientation, sex, race, ethnicity, and similar factors? Such discrimination is often a constitutional right - a right that's one of Chief Justice Rehnquist's and Justice O'Connor's important contributions to First Amendment jurisprudence. And many groups exercise this right...