The court's ruling overturns the conviction of Milwaukee grocery store owner Munir Hamdan. He was arrested in November 1999 when police found he was carrying a loaded gun in his pants pocket. His case is sent back to circuit court.
The high court also ruled the amendment guaranteeing the right to keep and bear arms does not overturn the state's 130-year-old ban on concealed weapons.
The concealed weapons law has been in place in Wisconsin since the 1870s. Wisconsin voters approved the right-to-bear-arms amendment in 1998. It says people have the right to keep and bear arms for security, defense, hunting, recreation or any other lawful purpose.
The court also upheld the 2000 conviction of Phillip Cole (the third). The Milwaukee man was convicted of carrying a concealed weapon after police found marijuana and two guns in his car during a routine traffic stop.