A federal appeals court on Tuesday refused to reconsider a ruling that struck down the District of Columbia's long-standing handgun control law, setting up a potential showdown in the Supreme Court over the Second Amendment.

The decision by the full U.S. Court of Appeals for the District of Columbia Circuit comes nearly two months after a three-judge panel rejected the city's argument that the Second Amendment right to bear arms applies only to state militias.

The panel ruled 2-1 that the city cannot prevent people from keeping handguns in their homes. The ruling also struck down a requirement that owners of registered firearms keep them unloaded and disassembled.

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The decision marked the first time a federal appeals court has struck down a portion of a gun law on Second Amendment grounds.

The city has 90 days to file a petition for review in the Supreme Court, which could hear arguments as soon as this winter if it decides to hear the case, said Alan Gura, an attorney for the six plaintiffs.

"This case obviously has about a good a chance as any of making it to the Supreme Court," Gura said.

"We believe we'll prevail," he said.

D.C. Mayor Adrian M. Fenty said he was disappointed in the ruling and that the city would review its options before deciding what to do next.

Opponents of the city's gun ban say it prevents people from taking measures to protect themselves and their families. They say the high crime rates in the three decades that the laws have been on the books prove the restrictions are ineffective.

Fenty said losing the restrictions would be a blow to crime-fighting efforts. The city logged 169 homicides last year, down from 196 in 2005.

Washington and Chicago are the only two major U.S. cities with sweeping handgun bans. D.C.'s ban on owning handguns went into effect in 1976 and will remain in effect while the case is being appealed.

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