A policeman signals Thursday that a road in central London is closed after a suspect vehicle was abandoned near Downing Street. A terrorist plot to launch Mumbai-style attacks on Britain and other European countries has been intercepted by intelligence agencies. Dan Kitwood/Getty Images hide caption

itoggle caption Dan Kitwood/Getty Images

Pedro Leonardo Mascheroni, photographed at his home in October 2009, was indicted on federal charges of communicating classified nuclear weapons data. Heather Clark/AP hide caption

itoggle caption Heather Clark/AP

Sgt. 1st Class Phillip Carroll, with the 101st Airborne Division, patrols in the Arghandab River valley outside Kandahar, Afghanistan, this week. Debate in Washington is growing over the scope and duration of continued U.S. military operations in Afghanistan. David Gilkey/NPR hide caption

itoggle caption David Gilkey/NPR

Emma and Christopher Winfield at their home in Cape Coral, Fla., on Sept. 3. Their son, U.S. Army Spc. Adam Winfield, is accused of murdering civilians during his deployment to Afghanistan, a charge he and his family firmly refute. Erik Kellar/AP hide caption

itoggle caption Erik Kellar/AP

Soldiers monitor computer screens inside the U.S. Central Command's mobile headquarters, in this U.S. military photo from 2002. A major concern regarding cyber warfare is the difficulty in distinguishing military targets from civilian targets. Gary P. Bonaccorso/Getty Images hide caption

itoggle caption Gary P. Bonaccorso/Getty Images

The audience at New York University's Skirball Center for the Performing Arts voted 55 percent against the motion "Treat Terrorists Like Enemy Combatants, Not Criminals" after the Sept. 14 debate. Chris Vultaggio hide caption

itoggle caption Chris Vultaggio