President Obama's top counter-terrorism advisor has given the most detailed explanation yet of America's use of drone attacks to kill suspected terrorists.

President Barack Obama took to a White House podium a year ago Tuesday to tell the world that al Qaeda leader Osama bin Laden had been killed in a U.S. Navy SEAL raid. A year later, former White House counter-terrorism advisor and ABC News consultant Richard Clarke looks at what role bin Laden really played and how the world has changed since his death.

As White House counter-terrorism advisor John Brennan delivered a speech today defending the U.S. drone campaign against Taliban and al Qaeda militants, an audience member interrupted and delivered a minute-long speech of her own protesting the targeted killings and the death of al Qaeda leader Anwar al-Awlaki's U.S.-born teen son in Yemen.

In his final days, according to declassified documents released today, Osama bin Laden was still ordering attack after attack on "only the Americans," but it's not clear if any of his orders were being carried out. "I'm reminded of the final days of Adolf Hitler in the bunker in Berlin," said ABC News consultant and former White House counter-terror advisor Richard Clarke, "when he was giving orders for divisions and armies to be moved around and those divisions and armies didn't exist."

A real-life socialist comes to the Obama White House