WASHINGTON – The Supreme Court ruled unanimously Monday that the government can force colleges to open their campuses to military recruiters despite university objections to the Pentagon’s “don’t ask, don’t tell” policy on gays.

Justices rejected a free-speech challenge from law schools and professors who claimed they should not have to associate with military recruiters or promote their campus appearances.

The decision was a setback for universities that had become the latest battleground over the military policy allowing gay men and women to serve only if they keep their sexual orientation to themselves.

The ruling does not, however, answer broader questions about the policy itself. Challenges are pending in courts in Boston and Los Angeles that could eventually reach the high court.

Justices seemed swayed by the Bush administration’s arguments that after the terrorist attacks, and during the war in Iraq, the government had a responsibility to bolster its recruitment.

Chief Justice John Roberts said that campus visits are an effective recruiting tool. And, he said, “a military recruiter’s mere presence on campus does not violate a law school’s right to associate, regardless of how repugnant the law school considers the recruiter’s message.”

The 8-0 decision upheld a federal law that says universities must give the military the same access as other recruiters or forfeit federal money.

Justices ruled even more broadly, saying that Congress could directly demand military access on campus without linking the requirement to federal money.

“When you’re in the middle of war, even if it’s not a terribly popular one, courts are hesitant to tie the hands of the military,” said Jon Davidson, legal director of gay rights group Lambda Legal.