Earlier this year Elizabeth Warren's presidential campaign ran ads on Facebook that proposed breaking it up, and they were temporarily pulled. Now, after Mark Zuckerberg talked at company meetings about the threat she poses, and as Facebook affirmed its policy to not fact check political ads, the campaign is at it again. CNN points out a Warren ad (that you can view here, collected in Facebook's political ad library) that begins with a lie claiming Zuckerberg endorsed Donald Trump.

After admitting that's not true, the ad states "If Trump tries to lie in a TV ad, most networks will refuse to air it. But Facebook just cashes Trump's checks," while also claiming the site "already helped elect Donald Trump once." In a statement to CNN, Facebook spokesperson Andy Stone said "If Senator Warren wants to say things she knows to be untrue, we believe Facebook should not be in the position of censoring that speech." And so the ad stays up.