Inside a San Francisco radio studio, away from the glare of television cameras and during a workday, the two candidates for California governor faced off in their only one-on-one debate before election day.

Advertised as a “wide-ranging conversation” instead of a formal political debate, the one-on-one meeting between Democratic Lt. Gov. Gavin Newsom and Republican businessman John Cox was noteworthy for lacking the prime-time television audience that traditionally sees candidates competing for the most powerful and coveted political post in the nation’s most populous state.