Then-presidential candidate Rick Santorum speaks to reporters in the spin room Jan. 14 after the undercard portion of the Fox Business Network Republican presidential debate in South Carolina.
Scott Olson/Getty Images
President Obama and John Brennan, his top counterterrorism adviser, in the Oval Office on Jan. 4, 2010. Brennan is a key voice about who gets put on the "kill list."
Pete Souza/White House