The decision involved a chapter of the Christian Legal Society at the University of California's Hastings College of the Law.
The court ruled the college's requirement that recognized student groups accept "all comers" is reasonable but sent the matter back to the 9th U.S. Circuit Court of Appeals for consideration of whether the school enforces the requirement selectively.
The 5-4 decision, written by Justice Ruth Bader-Ginsburg, said the advent of social networking sites lessens the impact of not gaining university recognition, which would have allowed the group to communicate with members through university channels.
The Christian Legal Society argued university policy "systematically -- and impermissibly -- burdens most heavily those groups whose viewpoints are out of favor with the campus mainstream." The court, however, rejected the argument.
In a concurring opinion, Justice John Paul Stevens says the policy may have a bigger impact on religious groups than others because they tend to restrict their membership.
"But there is likewise no evidence that the policy was intended to cause harm to religious groups, or that it has in practice caused significant harm to their operations," Stevens wrote.
Justice Samuel Alito dissented, saying the college's requirements severely limit unpopular speech.
(Hastings Christian Fellow-Ship vs. Martinez et al, No. 08–1371)