Fears of a terrorist attack are not sufficient reason for authorities to search people at a protest, a federal appeals court has ruled, saying Sept. 11, 2001, "cannot be the day liberty perished."

A three-judge panel of the U.S. Court of Appeals for the 11th Circuit ruled unanimously Friday that protesters may not be required to pass through metal detectors when they gather next month for a rally against a U.S. training academy for Latin American soldiers.

Authorities began using the metal detectors at the annual School of the Americas protest after the 2001 terrorist attacks, but the court found that practice to be unconstitutional.

"We cannot simply suspend or restrict civil liberties until the War on Terror is over, because the War on Terror is unlikely ever to be truly over," Judge Gerald Tjoflat wrote for the panel. "Sept. 11, 2001, already a day of immeasurable tragedy, cannot be the day liberty perished in this country."

City officials in Columbus, Ga., contended the searches were needed because of the elevated risk of terrorism, but the court threw out that argument, saying it would "eviscerate the Fourth Amendment."

"In the absence of some reason to believe that international terrorists would target or infiltrate this protest, there is no basis for using Sept. 11 as an excuse for searching the protesters," the court said.

Columbus Mayor Bob Poydasheff and Police Chief Willie Dozier did not return messages seeking comment Saturday.

Michael Greenberger, law professor and director of the University of Maryland's Center for Health and Homeland Security, said the ruling could have broader implications if it is used to challenge aspects of the USA Patriot Act.

It was surprising, he said, coming from the conservative-leaning 11th Circuit, based in Atlanta, but the opinion was "very well reasoned" and reflected "conventional application of constitutional principles."

The Rev. Roy Bourgeois, a priest who founded the protest group called School of the Americas Watch, praised the ruling for safeguarding essential rights.

"I felt that they were using 9/11 as an excuse, along with the Patriot Act, to interfere with our First Amendment rights," he said. "They are using this to get around what the Constitution is really rooted in."

The metal detectors caused long lines and congestion outside the protest area, he said, comparing it to routing 10,000 people through a single security gate at an airport.

"It was not just an inconvenience, it was a nightmare. We couldn't get to the place of assembly in an orderly fashion," he said.

About 15,000 demonstrators attend the annual vigil, demanding the closing of the center, formerly called the School of the Americas. The facility at Fort Benning was reopened in 2001 as the Western Hemisphere Institute for Security Cooperation.

The protests began in 1990. This year's demonstration is scheduled for Nov. 20-21.