The United States has detained more than 83,000 foreigners in the four years of the war on terror, enough to nearly fill the country's largest football stadium.
The administration defends the practice of holding detainees in prisons from Afghanistan to Guantanamo Bay as a critical tool to stop the insurgency in Iraq, maintain stability in Afghanistan and get known and suspected terrorists off the streets.
Roughly 14,500 detainees remain in US custody, primarily in Iraq.
The detentions and interrogations have brought complaints from Congress and human-rights groups about how the detainees - often Arab and male - are treated.
International law and treaty obligations forbid torture and inhumane treatment. Classified memos have given the government ways to extract intelligence from detainees "consistent with the law," administration officials often say.