Colin McKenzie-Gude, 18, was arrested after police found bombmaking material and weapons in his home.
The sentencing of a former Bethesda, Md., honors student for possessing bomb-making chemicals has been postponed a week.
Collin McKenzie-Gude, 20, pleaded guilty in September. On Thursday, U.S. District Judge Peter J. Messitte rescheduled the sentencing for Jan. 14 and 15 after he ruled a key government witness, McKenzie-Gude's former friend, Patrick
Yevsukov, must be required to testify, as the defense wants.
The judge said Yevsukov has already been granted immunity for his statements.
Authorities found assault weapons, armor-piercing bullets and more than 50 pounds of chemicals in McKenzie-Gude's bedroom in July 2008. They also said he had a fake CIA badge and a map of Camp David with markings for the presidential motorcade route.
McKenzie-Gude's attorney has said his client was fascinated with explosives but never intended to hurt anyone.
The government said he assembled the arsenal to stop a presidential motorcade to Camp David and take a shot at President Barack Obama with a long-range rifle.
Yevsukov's lawyer said his client distanced himself from McKenzie-Gude when he became uncomfortable with the plan. McKenzie-Gude's lawyer questioned Yevsukov's credibility, denying the plot or even the existence of the map to Camp David.