Even in today’s atmosphere of heightened political rhetoric, the word "treason" stands out.

President Donald Trump used the word to question the actions of House Intelligence Chairman Adam Schiff, D-Calif., a key figure in investigating presidential actions that could lead to Trump’s impeachment in the House.

"Rep. Adam Schiff illegally made up a FAKE & terrible statement, pretended it to be mine as the most important part of my call to the Ukrainian President, and read it aloud to Congress and the American people. It bore NO relationship to what I said on the call. Arrest for Treason?" Trump wrote in a Sept. 30 tweet.

Rep. Adam Schiff illegally made up a FAKE & terrible statement, pretended it to be mine as the most important part of my call to the Ukrainian President, and read it aloud to Congress and the American people. It bore NO relationship to what I said on the call. Arrest for Treason? — Donald J. Trump (@realDonaldTrump) September 30, 2019

Here, we’ll take a closer look at Trump’s use of the word "treason." It’s a word that’s often misused, including when Trump used it to criticize Democratic reactions to his State of the Union address and when Democrats used the word to describe Trump’s Helsinki news conference with Vladmir Putin of Russia.

What does the Constitution say about treason?

The framers defined treason narrowly to keep it from being applied to simple difference of opinion. The Constitution, which mentions very few crimes specifically, defines treason this way:

"Treason against the United States, shall consist only in levying war against them, or in adhering to their enemies, giving them aid and comfort. No person shall be convicted of treason unless on the testimony of two witnesses to the same overt act, or on confession in open court.

"The Congress shall have power to declare the punishment of treason, but no attainder of treason shall work corruption of blood, or forfeiture except during the life of the person attainted."

The point of that definition "is to avoid the slippery slope" that ends with, "I disagree with your policies, so you are a traitor," Kermit Roosevelt, a University of Pennsylvania law professor, told PolitiFact last year.

On the most basic level, treason has to occur in wartime, or during an armed rebellion against the government. And with the possible exception of an American working against U.S. troops in a place like Afghanistan, "there is no treason occurring on any side now," Jed Shugerman, a legal historian at Fordham Law School, told PolitiFact last year.

Because the definition of treason is so narrow, charges have only been brought a few dozen times in the country’s history, and few since the end of World War II, which was the last officially declared war. The most recent treason indictment was that of Adam Gadahn in 2006. Gadahn, an American citizen charged with aiding the enemy by being an al-Qaida spokesperson, was killed by a drone strike before he could be put on trial.

Charges of treason have been prosecuted in relation to the Whiskey Rebellion in 1794; against Aaron Burr (who was acquitted); against Thomas W. Dorr, who set up a parallel government of Rhode Island in the 1840s (he was convicted but later pardoned); and a number of cases related to slavery and the Civil War.

There was a flurry of treason cases during and after World War II, including the poet Ezra Pound for pro-Axis propaganda (he was hospitalized for insanity) and the broadcast propagandists known as Tokyo Rose and Axis Sally (both of whom served prison time).

The rarity of treason charges can also be seen in the examples of actions that never drew a treason charge.

During the Cold War, for example, Julius and Ethel Rosenberg were convicted of espionage charges, not treason. And Jane Fonda was never charged with treason for allegations of anti-Americanism when she consorted with the North Vietnamese during the Vietnam War.

Origins of the Trump-Schiff battle

Trump has blasted Schiff for allegedly twisting his words, targeting him in several recent tweets. Trump appears to have been referencing comments Schiff made during testimony by acting director of national intelligence Joseph Maguire about a whistleblower complaint.

The complaint focused on a phone call between Trump and Ukrainian president Volodymyr Zelensky. During the July call, Trump urged Ukraine to investigate former Vice President Joe Biden, a potential challenger in the 2020 presidential election. Trump and his allies have charged, without evidence, that Biden forced Ukraine to remove its lead prosecutor in order to protect his son Hunter, who worked for a Ukrainian company that had been under investigation.

During Maguire’s testimony, Schiff presented a dramatized version of the call between Trump and Zelensky. Schiff noted as he began that he was paraphrasing Trump’s words.

"Shorn of its rambling character and in not so many words, this is the essence of what the president communicates: ‘We've been very good to your country. Very good. No other country has done as much as we have. But you know what? I don't see much reciprocity here. I hear what you want. I have a favor I want from you, though. And I'm going to say this only seven times, so you better listen good. I want you to make up dirt on my political opponent, understand? Lots of it. On this and on that. I’m going to put you in touch with people, not just any people. I’m going to put you in touch with the attorney general of the United States, my attorney general Bill Barr. He’s got the whole weight of the American law enforcement behind him. And I’m going to put you in touch with (presidential attorney) Rudy (Giuliani). You’re going to love him, trust me. You know what I’m asking and so I’m only going to say this a few more times, in a few more ways. And by the way, don’t call me again. I’ll call you when you’ve done what I asked.’

"This is, in sum and character, what the president was trying to communicate with the president of Ukraine. It would be funny if it wasn't such a graphic betrayal of the President's oath of office. But as it does represent a real betrayal, there's nothing the president says here that is in America's interest after all."

Later in the hearing, when Rep. Mike Turner, R-Ohio, pointed out that what Schiff said did not match the readout of the call, Schiff said his summary was "meant to be at least part in parody."

Does what Schiff said constitute treason?

Experts agreed that nothing Schiff has said or done constitutes treason.

Trump is blurring the distinction between loyalty to a president and loyalty to the United States, said Carlton Larson, a University of California-Davis law professor and author of The Trials of Allegiance: Treason, Juries, and the American Revolution.

That distinction was something the framers of the Constitution deliberately wrote in contrast to English law, which had allowed treason to encompass "undermining the king’s authority," Larson said.

Indeed, even if Trump was right about everything that Schiff did — if he had fabricated Trump’s words and presented them to Congress — it wouldn’t qualify as treason.