Presenter Sacha Baron Cohen poses at the British Academy of Film and Television Arts (BAFTA) Awards, at the Royal Opera House in London, England, Feb. 14, 2016. Photo: Reuters / Toby Melville.

British Jewish actor Sacha Baron Cohen warned that a proliferation of conspiracy theories and lies was threatening to “kill democracy” in an op-ed for Time magazine published on Thursday.

“A few times in my career, I have genuinely feared for my life….Today, though, I’m truly terrified—for the survival of democracy itself,” the “Who Is America?” star wrote in the article.

Baron Cohen, 48, cited a number of “unhinged lies and conspiracies,” such as the blood libel that Jews murdered Christian children and used their blood for religious rituals, and said these conspiracies “threaten to kill democracy as we know it.”

In several paragraphs, he targeted Facebook, which he lambasted last year for allowing hate speech to flourish on its platform, calling it “the greatest propaganda machine in history.”

Baron Cohen said Facebook had “repeatedly failed to block other disinformation and refuses to implement systemic reforms advocated by the Stop Hate for Profit campaign, of which I am a part.”

He further noted that Facebook “refuses to fact-check political ads and posts,” and recalled that it was continuously used as an outlet for white supremacists and Holocaust deniers.

“All these lies couldn’t come at a worse time,” Baron Cohen added. “Studies show that people are especially susceptible to conspiracies in periods of great uncertainty when they feel a loss of control over their lives and want answers to make sense of the world. Over the years, I’ve filmed people, who otherwise seemed to be good and decent, repeating lethal conspiracies—regurgitating the diet of lies that they have been fed hourly on social media.”

The actor issued a call to action ahead of the Nov. 3 US presidential election, encouraging voters to “choose truth over lies.”

“The fate of U.S. democracy now rests with voters and whether they stand up in record numbers and choose truth over lies,” he said. “As protesters outside the 1968 Democratic convention chanted after they were brutally beaten by police, ‘The whole world is watching’—and this time it’s to see whether our planet’s oldest democracy will endure or slide into autocracy.”