Among the ads that have since been traced back to Russian origins were many that used vicious stereotypes and scare tactics: they mocked gays, smeared immigrants, invoked the devil, and portrayed Hillary Clinton as in league with Muslim terrorists.

“The social media ads, posts and pages that have been revealed to come from Russian agencies or operatives in 2016 used explicitly anti-Black, anti-Muslim and anti-immigrant stereotypes to undermine the American electoral system, suppress voter turnout and fan the flames of racist hatred and violence,” Malkia Cyril, executive director of the Center for Media Justice, said in a statement to The Nation.

They achieved a staggering reach. From fake papal endorsements of Donald Trump to sinister claims about Clinton, bots pumped out one-fifth of all tweets during the month leading up to the election. That’s according to Emilio Ferrara, an assistant professor of machine intelligence at the University of Southern California. Ordinary people were unable to distinguish them from authentic tweets, he said.