Many of the ads mention the personal attributes of the person seeing them, such as gender or race. Facebook banned this approach after the 2016 Trump campaign used demographic information in an effort to suppress African-American turnout in swing states.

Yet Legum discovered Team Trump again using dirty tricks . This time, it has falsely put the same quotation in the mouths of two different African-American men portrayed in different ads, one old and one young: “Sir, you have really inspired me and brought back my faith in this great nation. From the bottom of my heart, thank you for all the work you are doing.”

Spreading hate

Other journalists have also discovered that Facebook is failing to abide by its own policies. “The most obvious flaw in Facebook’s new system is that it misses ads it should catch,” ProPublica reported. Among the examples it found: An ad by the Washington State Democratic Party that wasn’t screened, because Facebook’s algorithm didn’t recognize it as a political ad.

And Media Matters, a liberal watchdog group, wrote the following in response to Legum’s new reporting:

“This isn’t the first time Facebook has failed to detect policy violations by advertisers on the platform. In September, Media Matters found a series of ads from right-wing clickbait sites, conspiracy theorists, and extremists which violated Facebook’s policies on false content and discriminatory practices. These ads included: posts from white supremacist Paul Nehlen promoting another white supremacist; anti-Muslim false news; anti-LGBT content; and 9/11 truther, QAnon, and Pizzagate conspiracy theories.”

The central problem seems to be that Facebook is primarily using an artificial-intelligence algorithm to police ads — and the algorithm isn’t very effective.