In an unprecedented defence of one of the U.S.' most secretive and controversial counterterrorism tools, a top Obama administration official has described drone strikes as legal, ethical and wise. On the eve of the first anniversary of the killing of Osama bin Laden, John Brennan, President Barack Obama's Assistant for Homeland Security and Counterterrorism, said that the President had instructed his administration to be more open with the American people about the use of remotely piloted aircraft to carry out targeted strikes against perceived terrorists.