“We believe the process we put in place is a solid step, but we also know that initially there will be instances where we don’t catch ads that should have been labeled and the authorization process wasn’t completed by the person placing the ad,” Mr. Leathern said in the call.
The Fourth District race has received national attention because four Democrats are running to oust Representative Tom McClintock, a five-term Republican. Ms. Bateson’s main rival is Jessica Morse, who previously worked for the State Department and other agencies. Both are campaigning for office for the first time. Mr. McClintock has said he believes that his seat is safe.
To run, Ms. Bateson, who grew up in Roseville, Calif., took a leave of absence last year from her job as a political-science professor at the Massachusetts Institute of Technology. She moved from Boston back to her hometown, which is just outside Sacramento, with her husband, Vivek Krishnamurthy, who is a lawyer, and their three children. Ms. Bateson is running on a platform that includes protection of the Affordable Care Act.
Sierra Nevada Revolution, which is facing a complaint to the Federal Election Commission over its failure to register as a political organization, clashed with Ms. Bateson starting in March when the group endorsed Ms. Morse. It attacked Ms. Bateson for having challenged Ms. Morse’s credentials this year.
The group often posted its criticism of Ms. Bateson on Facebook. Mr. Smith said he was in control of the account when it posted its first ad blasting her, adding that he spent more than $3,000 of his own money on that ad and others.