SAN FRANCISCO — Regina Bateson had just finished an Easter egg hunt with her children on April 1 when her phone started buzzing. Take a look at Facebook, messages from her friends and colleagues urged.
Ms. Bateson, a Democrat running for Congress in the California primary on Tuesday, quickly opened up the social network. There, she saw what appeared to be a news article that painted her as underhandedly trying to torpedo the campaign of a rival Democratic candidate. When Ms. Bateson clicked through the article, she was directed to a Facebook page run by Sierra Nevada Revolution, a local progressive group she had clashed with in the past.
The article was not a news story, she found, but a political ad paid for by Sierra Nevada Revolution. And while Facebook rolled out new rules on April 6 mandating that campaign ads be clearly labeled and say who had purchased them, Sierra Nevada Revolution’s ad about Ms. Bateson continued to be targeted to local voters throughout that month without any of those disclosures.
“It was a perfectly targeted negative campaign ad, but the average person had no idea who had really written it or what their motivations were,” said Ms. Bateson, 35, who is running in the Fourth Congressional District, a mountainous stretch of land between Sequoia National Forest and Lake Tahoe. She said she was frustrated by Facebook’s inability to label the so-called article as a political ad.
Ms. Bateson’s experience underscores Facebook’s difficulties as the Silicon Valley company aims to prevent manipulation of its ad system in elections, especially as the midterms loom this November. While the company has introduced several measures to improve the transparency of political ads on its platform, some groups and individuals appear to be finding ways to flout the new restrictions — and Facebook has not been able to catch them.
That raises questions about whether there are other gaps. Apart from improving transparency of political ads, Facebook has announced that it will not run a campaign ad in the United States unless it verifies the advertiser through a Social Security number, that it will keep a public archive of all political ads so they are easily searchable and that it has added a “paid for” label atop campaign ads so users can get more information.
Paul Smith, the administrator of Sierra Nevada Revolution’s Facebook page, said that despite Facebook’s efforts, he was able to place other political ads — some about Ms. Bateson and some about other issues — without labeling them. He didn’t say how many.
There is another potential loophole in Facebook’s rules. It appears that one person can go through the verification process and then give the account to someone else. Mr. Smith, for instance, said that while Facebook had authenticated him as a political advertiser, he later handed over control of Sierra Nevada Revolution’s account to others. That meant others could have used his Facebook verification to post political ads without the social network’s knowing it was not him.
“They don’t know we are five people running it, or however many,” Mr. Smith said in a phone interview. “It’s also not consistent. Occasionally, we slip a political ad by Facebook because it’s not flagged.”
Rob Leathern, Facebook’s director of product management, said he was “grateful” that The New York Times had brought the actions of Sierra Nevada Revolution to the company’s attention. “We are looking into it because it’s against our policies to share passwords or give someone else access to a person’s Facebook account,” he said, adding, “We use signals such as two-factor authentication to detect and prevent this type of abuse, but steps like these won’t stop every attempt to game the system.”
Facebook is being driven by its failure in the 2016 American presidential election to stop Russian agents from using the platform to spread divisive messages to voters. In the aftermath, the company announced changes, including working with independent fact-checkers and starting a news literacy campaign to help people spot disinformation. Facebook also banned political ads from foreign groups in some elections, including Ireland’s recent abortion referendum.
The largest effort has focused on authenticating and cataloging campaign ads on Facebook. The system is a work in progress, executives said in a recent call with reporters. But they said they hoped the transparency requirements would deter bad actors — especially those from foreign nations — from meddling in American elections.
“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.
That first ad, which Facebook did not designate as a political ad, was titled, “Lose by any means necessary.” It accused Ms. Bateson of running a “scorched earth campaign” and helping the Republican candidate by turning on her fellow Democrats.
Another Sierra Nevada Revolution ad, which ran on Facebook on May 26 and mentioned Ms. Bateson and other topics, did not say who had paid for it, as required. Facebook said that it had made a mistake and that the ad was removed before being republished later with the correct label.
In total, Sierra Nevada Revolution ran 29 Facebook ads in May aimed at swaying people’s votes in California’s primary, according to Facebook’s ad archive.
Ms. Bateson said that her own campaign was not verified as a political advertiser by Facebook and had filled out the paperwork only in recent weeks. Her campaign was working with an outside digital advertising firm to run ads on Facebook.
But she worried that it would be too little, too late — especially since others have already made a mark through political Facebook ads that were not properly labeled.
“Here we are with people already voting by mail in the primaries, and we see serious problems with their system,” Ms. Bateson said of the social network. “We see that someone from here with local knowledge of our election can use Facebook to really influence people.”