Ruth Ben-Ghiat is a professor of Italian studies and history at New York University.

Since President Trump’s election in November 2016, optimists have gone on trying to reassure each other. “Our institutions will hold,” they say.

Our institutions will only hold, however, if they are defended with concrete actions. The lawsuit filed by PEN America in October 2018 against Trump shows how. It charges that he has violated the First Amendment in misusing his official powers to retaliate against speech he finds objectionable. He revoked press passes of White House reporters from outlets that criticize him. He issued an executive order to review postal rates as a way of punishing Amazon, whose founder and chief executive, Jeff Bezos, owns The Post, which was Trump’s real target in this operation. (Those rates were raised in January.)

And just this week, he has suggested that Americans boycott AT&T as a way of punishing CNN, a network he views as his nemesis. He’s even been to known to share images that could encourage violence against CNN employees, such as a meme of him with a bloodied CNN logo on the bottom of his shoe.

Freedom of the press is at serious risk, thanks to Trump’s years-long crusade to discredit the media and his creation of a climate of hostility against journalists that is unparalleled in American history. There is evidence that attitudes have already changed among Republicans in ways that threaten liberty of expression. Almost half of Republicans polled by Ipsos in 2018 believed that the president should have the right to close news outlets for “bad behavior.”

Professor Kim Lane Scheppele of Princeton University and I address this creeping authoritarianism in an amicus brief we filed last month in support of the PEN lawsuit. The brief argues that Trump’s actions are based on the “autocratic playbook” that has been used effectively by rulers in Hungary, Poland, Russia, Turkey and elsewhere to domesticate the media and create the optimal conditions for leaders to consolidate their power and engage in corruption with impunity.

These new authoritarian states keep a veneer of democracy but make actual democratic participation, such as free voting and free expression, difficult and dangerous. Russia’s Vladimir Putin, Hungary’s Viktor Orban and Turkey’s Recep Tayyip Erdogan have taken steps to undermine the public’s trust in the media, block access to media outlets viewed as critical of the regime, harm the interests of owners of disfavored media organizations, and punish or censor disfavored journalists and media organizations. Hundreds of journalists falsely accused of terrorism are now serving sentences or in pretrial detention in Turkey, while Russian opposition journalists regularly meet with “accidents” that silence them for good.

Orban has so far managed to bring the media to heel without either mass arrests or assassinations, pulling off a spectacular mass genuflection in 2018 by media luminaries who “donated” almost 500 media properties to a government-allied foundation. In that year’s parliamentary elections, “opposition views could not even reach significant portions of the electorate,” according to the Mertek Media Monitor, just as Orban intended.

All these rulers have been in power for years, whereas Trump is just getting started — and regularly jokes about staying in office for a decade. Those who know him well are open about his lust for more power. The president “would love to have the [political] situation Viktor Orban has,” longtime Trump crony and current U.S. ambassador to Hungary, David Cornstein, recently stated.

Trump has long made clear how he would deal with the American media if he had the opportunity: harassment and libel suits against journalists who displease him, attempts to have broadcast licenses revoked, and jail time for those who won’t reveal their sources for leaked classified information. “It’s frankly disgusting the way the press is able to write whatever they want to write,” he stated in 2017, making no secret of his belief that it is his right, in his proprietary conception of the presidential office, to use his executive power for self-protection.

As the amicus brief notes, the United States could undergo the same backsliding from its democratic foundations that has taken place in other countries.

Although it might be more proper to say we have continuously had “democracy for whites only,” given slavery and Jim Crow laws, it’s a fact that Americans have had no national experience of authoritarian repression. We have never experienced military coups. We have never been occupied by Nazis, or endured decades of Communist dictatorship. This is our great fortune, but right now, faced with a leader of obvious authoritarian inclinations, it might also be a liability. Not only do many Americans take for granted their precious liberties, including freedom of expression, but they also are ill-equipped to recognize the warning signs of the decline of democracy and the rise of something else.

It is too easy to proclaim that “the institutions will hold” and leave it to others to do the holding. Each of us can mobilize with courage and love for our democracy to take action, making use of our specific talents and expertise. I and the other signatories of the amicus brief in support of the PEN America lawsuit have used our knowledge of how authoritarian regimes undermine the rule of law and take away our freedoms to warn the United States: It can happen here.