Last November, six members of Congress, all Democrats, posted a video that reminded U.S. military personnel of their duty to "refuse illegal orders." That well-established principle, which is reflected in the Defense Department's Law of War Manual, is legally uncontroversial. And as a federal judge later noted, the video was "unquestionably protected" by the First Amendment. President Donald Trump nevertheless insisted that the legislators had committed a grave crime.

"It's called SEDITIOUS BEHAVIOR AT THE HIGHEST LEVEL," Trump wrote on Truth Social. "Each one of these traitors to our Country should be ARRESTED AND PUT ON TRIAL." He added that "their words cannot be allowed to stand" because "we won't have a Country anymore!!!" He later reiterated that the legislators who produced the video had engaged in "SEDITIOUS BEHAVIOR," which he claimed is "punishable by DEATH!"

That apoplectic reaction, which led to an attempted federal indictment, was part of a familiar pattern. Again and again during the last decade, Trump has accused people who irk him of treason, sedition, or both. But those words do not mean what he thinks they do, and for good reason: Through centuries of bitter experience, Americans have learned the perils of letting the government define treason and sedition broadly enough to criminalize dissent. Although Trump clearly has not absorbed those lessons, his habitual invocation of these terms is a useful reminder of why U.S. law makes it so difficult to prove such charges.

Article III, Section 3 of the Constitution says "treason against the United States shall consist only in levying war against them, or in adhering to their enemies, giving them aid and comfort." It adds that "no person shall be convicted of treason" unless two witnesses testify to "the same overt act" or the defendant confesses "in open court."

That stringent definition of treason was a response to historical abuses, which extended the concept to include thought crimes, offensive remarks, religious dissent, and other nonviolent conduct that did not entail armed rebellion or siding with the nation's wartime enemies. The statutory definition of treason tracks the language of the Constitution.

That law does authorize a maximum penalty of death, which probably was what Trump had in mind when he condemned the "traitors" who appeared in the video that offended him. But nothing they said or did came remotely close to the elements of this crime.

What about sedition? Contrary to what Trump implied, there is no such stand-alone crime under the current U.S. Code. But federal law defines "seditious conspiracy" as a plot to "overthrow, put down, or to destroy by force the Government of the United States, or to levy war against them, or to oppose by force the authority thereof, or by force to prevent, hinder, or delay the execution of any law of the United States, or by force to seize, take, or possess any property of the United States contrary to the authority thereof." That also seems far afield from urging members of the armed forces to defend the Constitution and respect the law, which is what the legislators did in that video.

Eager to deliver on the president's threat, Jeanine Pirro, the Trump-appointed U.S. attorney for the District of Columbia, reportedly turned to 18 USC 2387, which applies to someone who "causes or attempts to cause insubordination, disloyalty, mutiny, or refusal of duty by any member of the military or naval forces of the United States." That crime, which is punishable by up to 10 years in prison, requires an "intent to interfere with, impair, or influence the loyalty, morale, or discipline of the military or naval forces of the United States." And as relevant here, the Uniform Code of Military Justice defines insubordination as willfully disobeying a "lawful order," while the video explicitly addressed "illegal orders."

How bad was the fit between Section 2387 and the political speech that Pirro claimed it covered? So bad that a grand jury rejected her proposed indictment in February—a remarkable setback, since grand jurors, who hear only the government's side of a case, almost always approve charges recommended by federal prosecutors. Two weeks later, NBC reported that Pirro had decided to drop the case.

The fact remains that the president of the United States wanted to imprison six members of Congress for saying things he did not like. And instead of trying to dissuade him, a federal prosecutor tried to make his revenge fantasy come true.