Although the Constitution says the government cannot "establish" or promote religion, the framers did not intend for God to be stripped from public life, Scalia said Sunday at a religious ceremony.
He contended that the Constitution has been misinterpreted both by the Supreme Court and lower courts. As an example, he pointed to a federal appeals court ruling in California barring students from reciting the Pledge of Allegiance with the phrase "one nation under God."
That decision is on hold pending further consideration by the same court, but the Supreme Court could eventually be asked to review the case.
Scalia, the main speaker at an event for Religious Freedom Day, said past rulings by the Supreme Court gave the judges in the pledge case "some plausible support" to reach that conclusion.
However, he said, such decisions should be made legislatively, not by courts.
The rally-style event about 50 miles south of Washington drew a lone protester, who silently held a sign promoting the separation of church and state.
"The sign back here which says 'Get religion out of government' can be imposed on the whole country," Scalia said. "I have no problem with that philosophy being adopted democratically. If the gentleman holding the sign would persuade all of you of that, then we could eliminate 'under God' from the Pledge of Allegiance. That could be democratically done."
The crowd repeatedly cheered Scalia, whose son Paul, one of nine children, is a priest at a nearby Roman Catholic church.
Several hundred people joined the justice in singing "God Bless America" after a brief parade through downtown sponsored by the Knights of Columbus.
"He's the voice of reason on the Supreme Court," said Jim McFall, a retired FBI agent who organized the parade. "His remarks were right on the money. The pendulum has swung too far and people have said 'enough is enough.' We'll see it swing back."
Scalia used the event to reiterate criticisms that the Constitution is being liberally interpreted.
"It is a Constitution that morphs while you look at it like Plasticman," he said.