President Barack Obama declared Monday night that the U.S. military action in Libya had "stopped (Moammar) Gadhafi's deadly advance," fulfilling what he said was a U.S. responsibility not to "turn a blind eye to atrocities in other countries."
"It may not happen overnight, as a badly weakened Gadhafi tries desperately to hang on to power," the president said. "But it should be clear to those around Gadhafi and to every Libyan that history is not on Gadhafi's side."
In a nationally televised address from the National Defense University in Washington, Obama sought to convince a skeptical Congress and a doubting nation that he was doing the right thing by intervening militarily in a third Muslim nation. He did that by casting the conflict as a moral response to oppression by Libya's leader, whom he called "a tyrant."
Top stories: Turmoil in the Middle East
The administration has struggled to make clear what it hopes to achieve in Libya, where U.S. forces were sent March 19 while Obama was out of the country on a South American tour.
In a Gallup poll released last week, 47 percent of respondents said they backed the campaign, the lowest level of support ever recorded in a poll taken at the beginning of a U.S. military action.
The campaign has also run into stiff resistance from members of both parties in Congress, who have complained that Obama did not consult them ahead of time. Rep. Dennis Kucinich, D-Ohio, accused Obama of having committed "an impeachable offense."
Obama acknowledged that "Americans continue to have questions about our efforts in Libya." To allay those concerns, he stressed that enforcing reform in Libya "will be a task for the international community and, more importantly, a task for the Libyan people themselves."
The U.S. role will be "limited," he said, promising that he would not send ground troops into the country.
Obama said the U.S. was just one part of a broad international coalition that had no choice but to act after Gadhafi rejected its ultimatum to "stop his campaign of killing or face the consequences."
The military action will be turned over to NATO leadership Wednesday, he said, and "the United States will play a supporting role" — mainly intelligence, logistical support and search-and-rescue operations.
"Because of this transition to a broader, NATO-based coalition, the risk and cost of this operation to our military and to American taxpayers will be reduced significantly," he said.
Other political news of note
Finger-pointing begins on do-nothing Congress
First Read: With Congress on pace to become the least productive ever, political parties begin the blame game as 2014 elections loom.
- Budget deal takes shape as deadlines loom
- Gas tax increase may be packaged as 'user fee'
- Obama: Income gap threatens our 'way of life'
- GOP faces choices on Obamacare attack
- Finger-pointing begins on do-nothing Congress
Libya not a template, administration says
Before the speech, Obama's deputy national security adviser, Denis McDonough, told reporters that Americans should not be worried that the intervention in Libya could open the door to further U.S. action in the Muslim world, where U.S. forces are already on the ground in Afghanistan and Iraq.
"It's not an international thing," McDonough said, insisting, like Obama, that the Libyan action was unique.
"We don't get very hung up on this question of precedent, because we don't make decisions about questions like intervention based on consistency or precedent. We base them on how we can best advance our interests in the region," he said.Video: What if Libyan mission doesn’t go as planned? (on this page)
Obama echoed that assessment, saying the U.S. was simply playing its "unique role as an anchor of global security and advocate for human freedom."
"It is true that America cannot use our military wherever repression occurs," he said. But "that cannot be an argument for never acting on behalf of what's right. In this particular country — Libya — at this particular moment, we were faced with the prospect of violence on a horrific scale. ...
"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."
No targeting of Gadhafi
But Obama said that was as far as the U.S. was willing to go, cautioning that "broadening our military mission to include regime change would be a mistake."
"If we tried to overthrow Gadhafi by force, our coalition would splinter," he predicted. "We would likely have to put U.S. troops on the ground or risk killing many civilians from the air.
"To be blunt, we went down that road in Iraq," he said — a road that took eight years to travel. "That is not something we can afford to repeat in Libya."
Sen. John McCain, R-Ariz., criticized Obama for promising Gadhafi that he wouldn't be overthrown by force, saying in an interview on CNN that "Gadhafi must have been somewhat comforted by that."
Other members of Congress also had reservations.
"Tonight's speech left many questions unanswered," said Sen. Rob Portman, R-Ohio, a member of the Armed Services Committee, who said Obama "has yet to clearly define the scope of our mission, the metrics for success and our ultimate goal."
House Speaker John Boehner, R-Ohio, also complained that Obama gave "few new answers."
"Nine days into this military intervention, Americans still have no answer to the fundamental question: What does success in Libya look like?" Boehner said.
Adam Smith of Washington, the ranking Democrat on the House Armed Services Committee, said he, too, "had some concerns with the level of communication between the administration, Congress and the American people." But he welcomed Obama's explanation of his "rationale for leading an international effort to prevent a humanitarian crisis in Libya."
"While the administration could have done a better job of working with Congress in the days prior to taking action, it is clear that U.S. leadership prevented this humanitarian crisis from getting worse and saved thousands of lives," Smith said. "As a nation, that is something we should be proud of."
Luke Russert and Kelly O'Donnell of NBC News contributed to this report from Washington.
© 2013 msnbc.com Reprints