Wilson's concerns proved prescient. Just two decades later, former Vice President Aaron Burr was charged with treason for allegedly writing to British officials, seeking money and warships to help him rally western states to secede from the Union. John Marshall, chief justice of the Supreme Court, presided over the trial. Burr was acquitted in 1807 because the government's case lacked the direct proof and witness statements required under the Constitution.
Partly because of its rarity, the formal charge of treason has conferred enduring infamy to many of those who have faced it. World War II broadcasters Iva Ikuko Togui D'Aquino and Mildred Gellars - known to American soldiers in Japan and Germany as "Tokyo Rose" and "Axis Sally" - both were convicted of treason after the war and served prison sentences.
The Idaho-born poet Ezra Pound was charged with treason for his Italian broadcasts that supported Hitler and Mussolini and decried the U.S. war effort. Instead of standing trial, Pound was declared insane and committed to a Washington, D.C., asylum.
`She didn't fire that gun'
For a time in the early 1970s, calls resounded from many quarters of America for Jane Fonda's name to join those ranks.
Fonda's opponents argued that she had offered aid and comfort to the North Vietnamese during her July 1972 trip to Hanoi, where she was accompanied by uniformed Vietnamese fighters and delivered 10 anti-American radio broadcasts. In one, she said that "Nixon will never be able to break the spirit of these people; he'll never be able to turn Vietnam, north and south, into a neo-colony of the United States by bombing, by invading, by attacking in any way."
Angry Americans said Fonda's actions fell in line with those of the World War II broadcasters who faced treason charges. But administration officials, who were eager to wind down the war effort and boost President Nixon's re-election campaign, viewed the case as a free-speech issue and were not eager to make a martyr out of a prominent anti-war activist.
"She didn't fire that gun," said William T. Mayton, an Emory University law professor, referring to the anti-aircraft artillary guns that Fonda was photographed posing on during her Hanoi trip. "She just sat on it. She was just making an anti-war statement."
Tomoya Kawakita is the last person in the United States to be charged with treason. Born in California, Kawakita had returned to his family's native Japan during the war and ended up working as a translator at prisoner of war camps, where he was accused of abusing American prisoners.
Convicted of treason after returning to the United States at the end of the war, Kawakita argued to the Supreme Court that he could not be guilty of treason, because he did not consider himself to be a U.S. citizen during his time in Japan. The court upheld his conviction, writing in 1952 that Kawakita could not claim a "fair-weather citizenship, retaining it for possible contingent benefits but meanwhile playing the part of the traitor."
"An American citizen owes allegiance to the United States," the court wrote, "wherever he may reside."