Trump’s grandiosity manifests itself in ways large and small. Through the first-person singular pronoun, he casts himself as the indispensable protagonist in the American story. At a Cabinet meeting last week, for example, he said, “I’m the one that did the capturing,” in reference to Islamic State terrorists. At another point, he said, “Look, I have the strongest economy ever.”

Perhaps the most extreme expression of Trump’s vaulting self-conception is his use of the word treason. Treason is a crime so serious that the framers took steps to ensure that it wouldn’t be misused for partisan purposes. It is a betrayal of one’s country, defined in Article III of the Constitution as levying war against the United States, or “adhering to” enemies and giving them “aid and comfort.” That’s not how Trump has sought to define it: disloyalty to a political leader or antipathy for that leader’s behavior.

Read: The unraveling of Donald Trump

Trump knows what treason means—or at least he once did. Talking to reporters aboard Air Force One in 2017, he described treason as Julius and Ethel Rosenberg passing secrets to the Soviet Union, acts of espionage that led to their execution in 1953. The word first popped up in his Twitter feed in September 2018, in reference to an anonymous op-ed in The New York Times describing how executive-branch officials resist Trump’s agenda. He has used the word two dozen times this year alone on Twitter, weaponizing it as his anger toward political opponents grows. Democrats who opposed his border measures, he tweeted in April, are “TREASONOUS.” Prosecutors working under Special Counsel Robert Mueller, he tweeted that same day, were perpetrating a “Treasonous Hoax!”

The latest enemy of the state is Democratic Representative Adam Schiff of California, the Intelligence Committee chairman who is running the impeachment probe. “I want Schiff questioned at the highest level for Fraud & Treason,” Trump tweeted last month. The crime: characterizing Trump’s phone call with the Ukrainian president, Volodymyr Zelensky, in a way that didn’t match the rough transcript released by the White House. That doesn’t sound like grounds for lethal injection, but Trump doesn’t seem to care. Conspiring with Schiff is another traitorous villain, Trump told his 66 million Twitter followers earlier this month: House Speaker Nancy Pelosi, who authorized the impeachment probe.

Trump’s use of the word is anachronistic in the modern era, echoing the way monarchs deployed it in centuries past. Carlton Larson, a professor at the UC Davis School of Law and an expert on treason, told me that Trump has misused the term in ways that “confuse loyalty to the country with loyalty to Trump, which is the old English idea that treason was betrayal of the king.

“He’s completely inaccurate, woefully so, in his understanding of it, and it’s quite disturbing,” Larson continued. “I can’t think of another president who has tossed around that term so casually. In many countries, treason is used as a way to execute political opponents—and it’s because of that that we have a more limited definition.”