But the 19-year-old Salt Lake County man says he does not intend to harm President Bush with anything more than a vote for John Kerry come November.
Just to be sure, though, agents from the Secret Service recently paid Kjar a visit, telling him that his neighbors had alerted them to a potentially threatening bumper sticker on his car.
The sticker, which can be found on a number of Web sites, features a black-and-white likeness of Bush, a crown tilted slightly on his head. Under the image are the words "KING GEORGE - OFF WITH HIS HEAD."
Glen Passey, agent in charge of the Secret Service's Salt Lake City office, would not confirm that agents visited Kjar.
But Passey said his office investigates all threats against the president.
"Oh, please," said David Hudson, a research attorney who works for the First Amendment Center at Vanderbilt University. "It's political hyperbole. However distasteful you might think it is, it's pure political speech."
Hudson said the message would never qualify as a true threat under the law.
But Kjar didn't know that. He said the agent he contacted in response to a cryptic message left on his voice mail would not even say why he wanted to talk - only that he wanted to meet Thursday morning.
That's when Kjar began to cry. "I didn't know what the hell was going on," he said. "It made me so nervous."
Kjar said two agents visited him at his job at a dry cleaning service, where they asked him about whether he had any ties to terrorist groups or enjoyed reading historical accounts of assassinations. They also asked Kjar about his friends and family, and even wanted to know how he paid his monthly rent.
The agents finally left after Kjar handed over the sticker.
Kjar said he feared the agents were going to "take me away."
Now, he feels as if they did.
"I kind of feel trapped, like I'm not allowed to express my opinions. I felt like my freedom of speech was shot to hell right there."
Dani Eyer, director of the Utah chapter of the American Civil Liberties Union, said Kjar's experience exemplifies the "chilling effect" government actions can have on free speech.
She cited U.S. Supreme Court rulings that protect exaggerated political expression.
In 1969, for instance, the high court overturned the conviction of a man who said he wanted to place President Johnson in the sights of his rifle if he were ever to be drafted.
"While direct advocacy of immediate violence can possibly be a crime, context is everything," Eyer said. "Only someone who has never read the Declaration of Independence and never heard of King Louis XVI could have mistaken revolutionary war rhetoric for a criminal threat."