"To brush aside America's responsibility as a leader and -- more profoundly -- our responsibilities to our fellow human beings under such circumstances would have been a betrayal of who we are," he told a crowd of military leaders gathered at the National Defense University at Ft. McNair in Washington, D.C. "Some nations may be able to turn a blind eye to atrocities in other countries. The United States of America is different. And as President, I refused to wait for the images of slaughter and mass graves before taking action."
Obama highlighted the success of the U.S. and allied mission so far in halting the advance of loyalist forces on the city of Benghazi, where Qaddafi had pledged to crush the rebels and go door-to-door pulling people from their closets, and in averting a humanitarian crisis.
But he cautioned against repeating the same type of mistake of forcing regime change as the U.S. tried in Iraq eight years ago, only to commit U.S. troops to a bloody and costly war and a country still trying to stabilize itself.
"Of course, there is no question that Libya -- and the world -- will be better off with Qaddafi out of power," he said. "I, along with many other world leaders, have embraced that goal, and will actively pursue it through non-military means. But broadening our military mission to include regime change would be a mistake."
More broadly, Obama addressed his insistence on spending weeks winning international support for the military mission at the United Nation's Security Council before sending in U.S. troops, a decision he said is critical to the success of the U.S. and its coalition allies' military intervention in Libya and long-term U.S. interests in the region.
"The transition to a legitimate government that is responsive to the Libyan people will be a difficult task," he said. "And while the United States will do our part to help, it will be a task for the international community, and -- more importantly -- a task for the Libyan people themselves."
"If [the United States] tried to overthrow Qaddafi by force, our coalition would splinter. We would likely have to put U.S. troops on the ground, or risk killing many civilians from the air," he said. "The dangers faced by our men and women in uniform would be far greater. So would the costs, and our share of the responsibility for what comes next."
The speech comes as Congress, deeply divided over U.S. military action in Libya, returns from a week-long recess. Members from both parties have been clamoring for more consultation and have spent the last week harshly criticizing Obama's approach, as well as his delay in articulating a clear message to the American people about the strategy behind his decisions.
There are several congressional hearings planned for Wednesday, which will give the administration a chance provide more detail and lawmakers a platform to grill officials about the military action and efforts to woo international partners before sending the U.S. military to Libya to lead costly air strikes aimed at taking out the regime's critical defense installations.
Obama delivered the remarks as rebel forces under cover of UN-mandated air strikes closed in on Sirte, Qaddafi's hometown and a key regime stronghold, where loyalist troops readied for what could turn out to be a key battle of the war. Despite a Libyan rebel claim early Monday that Sirte had been captured, there was no sign that the opposition was in control of the city, which marks the boundary between eastern and western Libya and control of it could pave the way to a rebel march on Tripoli some 280 miles away.
After a wave of air strikes targeted Sirte Sunday night and Monday morning, British Prime Minister David Cameron and French President Nicolas Sarkozy issued a joint statement calling on Qaddafi loyalists to abandon the dictator. Obama held a videoconference with Cameron, Sarkozy and German Chancellor Angela Merkel Monday afternoon in which Obama reiterated his pledge to continue providing support capabilities to the coalition effort and the European leaders discussed Tuesday's international conference on Libya in London.