WaPo:

Fact checkers were unanimous in their assessments when President Trump began claiming in June that Democrat Joe Biden wanted to “defund” police forces. Politifact called the allegations “false,” as did CheckYourFact. The Associated Press detailed “distortions” in Trump’s claims. FactCheck.org called an ad airing them “deceptive.” Another site, The Dispatch, said there is “nothing currently to support” Trump’s claims.

But these judgments, made by five fact-checking organizations that are part of Facebook’s independent network for policing falsehoods on the platform, were not shared with Facebook’s users. That’s because the company specifically exempts politicians from its rules against deception. Ads containing the falsehoods continue to run freely on the platform, without any kind of warning or label.

Enabled by Facebook’s rules, Trump’s reelection campaign has shown versions of the false claim on Facebook at least 22.5 million times, in more than 1,400 ads costing between $350,000 and $553,000, a Washington Post analysis found based on data from Facebook’s Ad Library. The ads, bought by the campaign directly or in a partnership with the Republican National Committee, were targeted at Facebook users mainly in swing states such as Ohio, Georgia, North Carolina, Florida, and Pennsylvania.