Something’s been nagging me as I watch President Trump talk about himself incessantly, repeating his fantastical and obsessive belief that he got the most votes, his crowd was the biggest, his ratings unmatched. I felt a twinge of déjà vu over his attacks on the press, his discrediting of opposition, his ramming through orders before vetting them, his readiness to fire senior officials who oppose him.

Then I realized: It reminds me of a very, very long day I spent with Venezuelan strongman Hugo Chávez.

Chávez rode to power in elections on a populist wave and a Messianic brand as savior of the masses and bedeviler of the elites. Like Trump, he was a skilled communicator and self-aggrandizer who made a visceral connection with his passionate base. He promised social programs, and thanks to oil sales, he delivered. He bullied the opposition and muzzled the press. And he had an epic, Fidel Castro-like ability to ramble on his weekly soapbox — for eight hours straight the day I spent with him in 2005 — as he live-broadcast his “Aló Presidente” TV show, a precursor to Trump’s Twitter. A Venezuelan political scientist told me at the time, “He’s a fantastic liar, but I think he really believes what he says.” He won successive elections, serving for 14 years until he died.

Is it fair to compare Trump to Chávez? I asked Moises Naim of the Carnegie Endowment for International Peace in Washington, a former Venezuelan minister of trade and Central Bank governor, one of those elites whom Chávez so reviled. Naim knew Chávez, and he’s created a new 60-hour biopic series on Chávez’s life called “El Comandante.” To Naim, the parallels are real and alarming.

“In Trump, the narcissism is more pronounced than with Chávez,” he said, but Trump “is not a uniquely American creation. He belongs to a long line and old type of politician that uses populism” not as ideology, but to acquire and retain power. Populist authoritarianism “thrives on division: ‘us’ vs. ‘them’ – the elite who ran things before” — with internal enemies, like Hillary Clinton, and external ones, like Mexicans, Muslims and China — “and on completely delegitimizing media and experts.” Russia’s Vladimir Putin and Iran’s mullahs use the same tactics, he added.

Naim believes Trump will be a test of our Founders’ limits on the concentration of power. He’s not alone; old classics are sudden bestsellers on Amazon.com: George Orwell’s dystopic “1984” and Sinclair Lewis’s 1935 novel “It Can’t Happen Here,” about an American politician who campaigns on patriotism and traditional values and imposes plutocratic, totalitarian rule.

In a national poll during the campaign, Matthew MacWilliams of the University of Massachusetts Amherst, found the single most important factor predicting support for Trump was not race, age, gender or income, but inclination to authoritarianism. Trump knew that instinctively and capitalized on it. “I alone can fix it,” he vowed.

Before Trump began rapidly issuing edicts, like the refugee ban that sparked widespread protests, “I would’ve said my biggest fear was democracy would be slowly eroded without people noticing. Now I think we’re headed for a giant clash,” said Yascha Mounk, a lecturer in government at Harvard who studies right-wing European populism. “Trump’s administration is going to be more authoritarian than I feared and the opposition is going to be more courageous than I expected.”

True authoritarianism is when independent institutions lose their independence, and there’s no reason to think the US government is as weak as Venezuela or pre-World War II Europe, said William Galston of the Brookings Institution. Galston lived through Richard Nixon (a hero of Trump’s) and points out an independent judiciary and press prevailed in that story. “I’ll put my faith in the Constitution and the American people,” Galston said.

But democratic norms can be eroded stealthily without our noticing, in an accumulation of small bureaucratic measures, the undermining of norms (like failing to release taxes or divest from businesses), and the abrogation of agreements. All of these things Trump has done or vowed to do. Clearly we should take him both seriously and literally.

Leaders like Chávez managed to use democratic institutions to erode democracy. Populist strongmen can succeed when the populace is complacent in that belief that “it could never happen here.”