A panel of federal judges is weighing whether to overturn a Cook County ban on semiautomatic weapons in a case that could upend other local bans and call into question the statewide prohibition on the controversial class of firearms.

The case went before the appellate court only four days after a conservative federal judge declared Illinois' statewide assault weapon ban unconstitutional.

U.S. District Judge Stephen McGlynn says the law bans firearms covered by the Second Amendment and is not supported by historical precedent.