SACRAMENTO — Two years after the U.S. Supreme Court removed legal barriers to sports betting, California voters could be asked in November to join 14 other states in allowing legal wagers on athletic contests, creating a lucrative industry worth billions of dollars and intense competition among rival gambling interests in the state.

On Tuesday, a coalition of 18 Native American tribes was given approval to begin circulating petitions for a statewide ballot initiative that would allow sports betting at tribal casinos and horse racing tracks, but not at rival card clubs or on the internet.