Undersecretary of State for Political Affairs Wendy Sherman testifies before the Senate Foreign Relations Committee in 2014. Sherman was the lead U.S. negotiator on the Iran nuclear deal. She stepped down from her post last week and is now teaching at Harvard. Charles Dharapak/AP hide caption

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Photos of victims of the mass shooting at Umpqua Community College in Roseburg, Ore., are displayed behind Portland Police Sgt. Peter Simpson (left) and Douglas County Sheriff John Hanlin. Rich Pedroncelli/AP hide caption

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U.S. soldiers in Afghanistan walk away from a helicopter at Forward Operating Base Connelly in the eastern province of Nangarhar on Aug. 13. The U.S. formally ended combat operations in Afghanistan at the end of last year. But nearly 10,000 American troops remain in the country and the U.S. frequently carries out air sorties. Fourteen American military personnel have died in Afghanistan this year. Wakil Kohsar/AFP/Getty Images hide caption

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The burned Doctors Without Borders hospital is seen after explosions in the northern Afghan city of Kunduz on Saturday. Doctors Without Borders says 12 staff members and 10 patients were killed in the attack and 37 others were wounded. AP hide caption

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"We don't collect a lot of your data and understand every detail about your life. That's just not the business that we are in," says Apple CEO Tim Cook, shown here at the NPR offices in Washington, D.C., on Thursday. Ariel Zambelich/NPR hide caption

itoggle caption Ariel Zambelich/NPR