Secretary of State Hillary Clinton speaks while Treasury Secretary Tim Geithner looks on during a Nov. 21 news conference about new sanctions against Iran. Pablo Martinez Monsivais/AP hide caption

itoggle caption Pablo Martinez Monsivais/AP

Iranian President Mahmoud Ahmadinejad waves in Pakdasht, southeast of Tehran, Nov. 23. Ahmadinejad on Wednesday said he was surprised at European moves to isolate Tehran's central bank. HO/Reuters/Landov hide caption

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Unmanned aerial vehicles, like this Predator (shown here in 2009 during training at Creech Air Force Base in Indian Springs, Nev.), make up the fastest growing segment of the U.S. Air Force. Ethan Miller/Getty Images hide caption

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Dr. Alex Dromerick co-directs the Brain Research Center at the National Rehabilitation Hospital. Here he observes Stephen Jones, a policeman who was involved in a motorcycle accident. Becky Lettenberger/NPR hide caption

itoggle caption Becky Lettenberger/NPR

The Predator drones flying over Afghanistan and Pakistan are variants of this MQ-9 Reaper. Lt. Col.. Leslie Pratt/U.S. Air Force via AP hide caption

itoggle caption Lt. Col.. Leslie Pratt/U.S. Air Force via AP

A U.S. Marine pushes a child on a swing in southern Afghanistan on March 4. After a decade of nation-building in Afghanistan, and nearly as long in Iraq, the U.S. appears to be losing it appetite for such efforts. Adek Berry/AFP/Getty Images hide caption

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A passenger removes his shoes at the TSA security checkpoint at John F. Kennedy International Airport — a task that may not be required in the near future, says Department of Homeland Security Secretary Janet Napolitano. Michael Nagle/Getty Images hide caption

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