It's a federal crime to threaten harm to the President of the United States or other federal officials. A Connecticut student recently was arrested on criminal charges for threatening President Obama. He allegedly sent an email to the White House, telling the president that if he would kill him if he didn't resign from office by the end of 2013.
The U.S. Secret Service arrested the man on the campus of the University of Connecticut where he was a student up until recently. Just prior to being arrested, he allegedly lost control and screamed that if Obama didn't "change," then "someone is going to do what I wrote..." The suspect has reportedly received treatment for mental health problems and was hospitalized recently in a psychiatric institution for a brief time.
In most state criminal courts these statements would not likely be sufficient to establish a criminal offense. The defendant expressed a present intent to kill in order to be guilty, and generally speaking, threats couched in the necessity that some future circumstance occur is not a criminal violation. Obviously, that's because of the speculative nature of the communication, which requires that unknown future events must happen to trigger the potential threat.
That's a good criminal defense but it may not hold up in a federal court. There the concern is more frenetic and guilt more likely to be imposed. Threats against the President, when in doubt, will be interpreted against the speaker and will bring serious charges. Nonetheless, the man's purported comment that if Obama didn't change, then someone would kill him is not only speculative but also raises issues of free speech.
In Connecticut, defense counsel may consider defending the criminal charges on the premise that the suspect was simply exercising free speech rights. The elaboration that Obama must "change" adds a political element, indicating perhaps a fiercely expressed political opinion but not one with a present intent to commit harm. In any event, it's also true that this defendant has a history of mental illness, and he is currently confined in a psychiatric institution for testing to determine his competency. A resolution that calls for mandatory mental health treatment may ultimately be acceptable to both sides.
Source: NBC Connecticut, UConn Student Accused of Threatening President Obama, No author, Nov. 21, 2013