WASHINGTON (AP) - President Barack Obama sought Thursday to advance the U.S. beyond the unrelenting war effort of the past dozen years, defining a narrower terror threat from smaller networks and homegrown extremists rather than the grandiose plots of Osama bin Laden's al-Qaida.
In a lengthy address at the National Defense University, Obama defended his controversial drone-strikes program as a linchpin of the U.S. response to the evolving dangers. He also argued that changing threats require changes to the nation's counterterrorism policies.
Obama implored Congress to close the much-maligned Guantanamo Bay detention center in Cuba and pledged to allow greater oversight of the drone program. But he plans to keep the most lethal efforts with the unmanned aircraft under the control of the CIA.
President Barack Obama pauses as his speech is interrupted by a heckler Thursday at the National Defense University at Fort McNair in Washington.
He offered his most vigorous public defense yet of drone strikes as legal, effective and necessary as terror threats progress.
"Neither I, nor any president, can promise the total defeat of terror," Obama told his audience of students, national security and human rights experts and counterterror officials. "What we can do - what we must do - is dismantle networks that pose a direct danger, and make it less likely for new groups to gain a foothold, all while maintaining the freedoms and ideals that we defend."
Obama's address came amid increased pressure from Congress on both the drone program and the status of the Guantanamo prison. A rare coalition of bipartisan lawmakers has pressed for more openness and more oversight of the highly secretive targeted strikes, while liberal lawmakers have pointed to a hunger strike at Guantanamo in pressing Obama to renew his stalled efforts to close the detention center.
The president cast the drone program as crucial in a counterterror effort that will rely less on the widespread deployment of U.S. troops as the war in Afghanistan winds down. But he acknowledged the targeted strikes are no "cure-all" and said he is deeply troubled by the civilians unintentionally killed.
"For me, and those in my chain of command, these deaths will haunt us as long as we live," he said. Before any strike, he said, "there must be near-certainty that no civilians will be killed or injured - the highest standard we can set."
In Pakistan alone, up to 3,336 people have been killed by the unmanned aircraft since 2003, according to the New America Foundation which maintains a database of the strikes. However, the secrecy surrounding the drone program makes it impossible for the public to know for sure how many people have been killed in in strikes, and of those, how many were intended targets.
In an attempt to lift the veil somewhat, the Justice Department revealed for the first time Wednesday that four Americans had been killed in U.S. drone strikes abroad. Just one was an intended target - Anwar al-Awlaki, who officials say had ties to at least three attacks planned or carried out on U.S. soil. The other three Americans, including al-Awlaki's 16-year-old son, were unintended victims.
Drones aside, some Republicans criticized Obama as underestimating the strength of al-Qaida in his speech and for proposing to repeal the president's broad authorization to use military force against the nation's enemies - powers granted to George W. Bush after the Sept. 11, 2001, attacks.
"I believe we are still in a long, drawn-out conflict with al-Qaida," Sen. John McCain, R-Ariz., told reporters after the speech. "To somehow argue that al-Qaida is on the run comes from a degree of unreality that to me is really incredible. Al-Qaida is expanding all over the Middle East, from Mali to Yemen and all places in between."