The court is agreeing to decide if the Constitution forbids the Bush administration from holding U.S. citizens indefinitely and without access to lawyers when they're labeled as "enemy combatants."
The court will consider the case of Jose Padilla, an American citizen who's been accused of being part of a plot to set off a radioactive bomb.
The Padilla case is similar to another terrorism case the court has already agreed to hear. Both cases will allow the justices to take their most comprehensive look yet at the rights of Americans captured at home or abroad in the War on Terror.
Lawyers for the suspects claim their treatment is unconstitutional. The Bush administration says the aim is to protect the nation and further pursue the campaign against terror.
The Supreme Court is expected to hear both cases in late April, with a ruling due by summer.