Elizabeth Warren put Facebook’s refusal to fact-check political ads to the test last week by posting an ad that falsely claimed “Breaking news: Mark Zuckerberg and Facebook just endorsed Donald Trump for re-election.”

The post immediately clarified that it was untrue, adding “What Zuckerberg *has* done is given Donald Trump free rein to lie on his platform — and then to pay Facebook gobs of money to push out their lies to American voters.”

She then complained, “Facebook has already helped elect Donald Trump once.”

Facebook has countered that it won’t censor politicians’ free speech, and would rather let the voters decide.