Authoritarianism expert Ruth Ben-Ghiat says Donald Trump is falling into the same trap that has undone authoritarian-minded leaders throughout history.

Despite declining approval ratings, Ben-Ghiat argued in a guest essay for The New York Times that the president is making the age-old error of believing his own hype.

“I have seen this brand of strongman megalomania and the adverse effects it can ultimately have on leaders and their governments,” wrote Ben-Ghiat, the author of “Strongmen: Mussolini to the Present.”

Ben-Ghiat, a professor of history at New York University, described the phenomenon as “autocratic backfire.” It occurs when leaders “cut themselves off from expert advice and objective feedback,” “promulgate unscrutinized policies that fail” and then “double down and engage in even riskier behavior,” she said.

“The result: a disillusioned population that loses faith in the leader and elites who begin to rethink their support,” she wrote, citing Italian dictator Benito Mussolini and Russian President Vladimir Putin as historical examples of the pattern she sees emerging around Trump.

Ben-Ghiat has long drawn parallels between Trump and past dictators.

She has previously noted that his bombastic self-praise echoes a fascist slogan from Mussolini’s Italy: “Mussolini is always right.”