Donald Trump has 17 million followers on Twitter, and is one of the most influential users on the social network. He has himself bragged that having so many followers is “like owning the New York Times without the losses.” And he has used that huge level of influence to preside over numerous campaigns of cyberbullying and abuse.

After Lauren Batchelder, an 18 year-old student in New Hampshire, questioned Trump about equal pay and reproductive rights at a campaign event last year, Trump took to Twitter and called her an “arrogant young woman.” His campaign staff then tweeted screenshots of her social media accounts, setting off a campaign of abuse and vitriol directed at Batchelder.

Online trolls rated her physical appearance, threatened to rape her, posted her home address online, and circulated a photoshopped picture of her face covered in semen. “Wishing I could f—ing punch you in the face. id then proceed to stomp your head on the curb and urinate in your bloodied mouth and i know where you live, so watch your f—ing back punk,” read one Facebook message sent to Batchelder, who also received numerous threatening voicemails, many of which were sexual in nature.

Becoming the president-elect has not stopped Trump from using his platform and influence to orchestrate online cybermobs against his critics. After Chuck Jones, the president of the union representing Carrier workers, criticized Trump for lying about how many jobs at Carrier Trump had supposedly saved, Trump attacked Jones on Twitter, prompting a torrent of online attacks directed at Jones and his family––along with several threatening phone calls to their home.

Too many incidents like this have happened for Trump to claim ignorance about the actions of his followers. Just as Trump has incited violence against protestors at his rallies, he has used his bully-pulpit on Twitter to silence and intimidate his critics. Now that he will soon occupy the highest office in the land, it’s even more urgent to stop this abuse now.

Twitter recently implemented new policies on hateful conduct and online abuse designed to end exactly this kind of behavior. These new policies prohibit users from engaging in abuse or harassment themselves—or inciting others to do so. As demonstrated in numerous cases, Trump’s Twitter activity exemplifies incitement of harassment and abuse. If Twitter’s new policies mean anything at all, Trump’s account should be immediately suspended.

While some may argue that Trump has a right to free speech, the First Amendment does not protect all speech. Harassment and threats of violence are not protected forms of speech, and neither is inciting people to harm others. Furthermore, Donald Trump—as the president-elect, as a billionaire, and as a reality TV star—is in no danger of losing his ability to be heard by the public. What is under threat is the ability for critics and dissenters of all kinds within our society to speak freely without fear of violence or harassment. Trump’s ability to harness social media to threaten and intimidate anyone who dares to criticize him is a threat not only to free speech, but to a free society.

Twitter, we call on you to adhere to your own rules governing online abuse—and also to fulfill your duty as citizens of the United States—by immediately suspending the account of Donald Trump. Twitter has already led the tech world as the only tech company to commit to refusing to help Trump build a registry for American Muslims. But now we need you to go further, and act to defend our democracy from Trump’s anti-democratic cybermob.