Conservative lawyer Larry Klayman persuaded a federal judge in December to rule that the agency's activities likely violate the Constitution's ban on unreasonable searches. The justices on Monday rejected Klayman's unusual request to bypass the traditional appeals process and hear the case immediately.
Klayman says the case is too important to wait for the U.S. Court of Appeals for the D.C. Circuit to reach a decision. The district court judge granted an injunction against the NSA, but put it on hold pending a government appeal.
The Obama administration has defended the NSA program as a crucial tool against terrorism.