Journalist Scott Shane says that the videos and DVDs of the late imam Anwar al-Awlaki (above) continue to inspire terrorist acts. Muhammad ud-Deen/AP hide caption

toggle caption Muhammad ud-Deen/AP

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 hide caption

toggle caption Pete Souza/White House