In the current term’s other major First Amendment case, the court seems likely, based on the justices’ questioning, to strike down a law banning the sale of violent video games to minors. Only the interest in national security has in the recent run of decisions been ruled substantial enough to overcome free-speech interests.

Chief Justice Roberts used sweeping language culled from the First Amendment canon in setting out the central place free speech plays in the constitutional structure. “Debate on public issues should be robust, uninhibited and wide-open,” he wrote, because “speech on public issues occupies the highest rung of the hierarchy of First Amendment values.”

The case decided Wednesday arose from a protest at the funeral of a Marine who had died in Iraq, Lance Cpl. Matthew A. Snyder. As they had at hundreds of other funerals, members of the Westboro Baptist Church of Topeka, Kan., appeared with signs bearing messages like “America is Doomed” and “God Hates Fags.”

The church contends that God is punishing the United States for its tolerance of homosexuality.

The father of the fallen Marine, Albert Snyder, sued the protesters for, among other things, the intentional infliction of emotional distress, and won a substantial jury award that was later overturned by an appeals court.

Chief Justice Roberts wrote that two primary factors required a ruling in favor of the church. First, he said, its speech was on matters of public concern. While the messages on the signs carried by its members “may fall short of refined social or political commentary,” he wrote, “the issues they highlight  the political and moral conduct of the United States and its citizens, the fate of our nation, homosexuality in the military and scandals involving the Catholic clergy  are matters of public import.”