BOULDER, Colo.— The U.S. Postal Service and a rural Colorado man argued in court Wednesday over where on postal property people can legally carry guns.

A three-judge panel of the 10th U.S. Circuit Court of Appeals heard arguments in the case involving Tab Bonidy, a licensed gun owner who, along with the National Association for Gun Rights, sued the Postal Service in 2010 over its ban on guns in post offices.

Bonidy said the post office in Avon, a small town near Colorado’s Vail and Beaver Creek ski resorts, violated his Second Amendment rights by refusing to let him carry his concealed handgun into the building when he picks up his mail. The post office also barred him from keeping the weapon in his vehicle in the parking lot.

U.S. District Judge Richard Matsch ruled last year that the Postal Service’s ban on firearms in its parking lots violated the Second Amendment. But he also said the agency could keep people such as Bonidy from carrying a gun in a post office lobby.

Both Bonidy and the Postal Service appealed. They disagree over what constitutes a “sensitive place,” such as a government building or a school, where guns can be legally banned.

Bonidy, 56, lives outside town and doesn’t get mail delivery. He travels regularly to the post office in Avon, where he doesn’t want the hassle of having to disarm just to briefly pick up and drop off letters in the lobby.

A 10th Circuit ruling would impact other rural Westerners who carry concealed weapons or travel with their hunting rifles and find themselves in the same position, Bonidy’s attorneys said.

Matsch wrote in his July 2013 order that because a postal building is sensitive, the sight of someone carrying a gun inside “may excite passions, or excited passions may lead to the use of the firearm. Someone could also attempt to take the firearm from its lawful carrier and use it for criminal purpose.”

But keeping Bonidy from storing the gun in his vehicle outside “sweeps too far” because the public safety concerns that exist inside the building don’t apply to the parking lot, the judge said.

“The Second Amendment guarantees the right to bear arms outside the home. Should he have to surrender that right to pick up his mail?” Bonidy’s attorney, Steven Lechner of the Mountain States Legal Foundation told the judges. “Not every government building is sensitive. There has to be some criteria or the government gets a free pass.”

But the Postal Service argues that the public safety interest in keeping guns out of its facilities trumps individual liberty. Department of Justice Attorney Daniel Tenny told the judges their decision could apply to the agency’s tens of thousands of buildings across the country. He said the blanket ban is a necessary safety measure.