Obama had opposed the Iraq war and ran for presidency on a promise to end it. The last batch American troops left Iraq in 2011.
"The President's position on whether or not the United States made a wise decision to invade Iraq 10 years ago was clear and remains clear: He does not believe that was the right choice, did not believe then, and his position has not changed," White House Press Secretary Jay Carney told reporters at his daily news conference.
"What is absolutely the case is that our men and women in uniform, the most professional military that the world has ever known, when given an assignment, regardless of whether the assignment was the right policy choice or not, fulfill their mission and do it heroically and professionally," he argued.
"That is the case with regards to Iraq, and it is certainly the case with regards to Afghanistan. So the fact that Iraq is in a place, as difficult as its challenges remain, where it has the potential for a better future, is due in no small measure to the sacrifice and service of American men and women. It's also obviously due to the courage and perseverance of the Iraqi people, and we should note that," he said.
Carney said the US President has made his judgments clear about the invasion.
"Historians will and the American people will over the years make their own judgments," he said.
"It is not a mystery, that the President, as a Senate candidate and then a senator, opposed the invasion of Iraq, opposed the Iraq War, and, as a candidate in 2008, promised to end the Iraq War, and he has fulfilled that promise," he said.
The situation in Iraq continues to be a challenge, he noted.
"But there is an elected government. There is a growing economy. There is certainly the potential and prospect for Iraq to have a much better future than its past. That is due to, in significant measure, the sacrifice and service of Americans," he added.
Meanwhile in a statement on the 10th anniversary of the start of the war, Obama honoured the memory of the nearly 4,500 Americans who made the ultimate sacrifice to give the Iraqi people an opportunity to forge their own future after many years of hardship.
"We express our gratitude to our extraordinary military families who sacrificed on the home front, especially our Gold Star families who remain in our prayers," he said.
US Defense Secretary Chuck Hagel said the American people will always honour the sacrifices of the 4,475 US service members who died in Iraq, and the more than 32,000 who came home wounded.
"Our reflections include the Iraqi people - the Iraqi soldiers and police officers who died alongside our own, the men and women who were caught in the crossfire, and those who still struggle today to secure and govern their nation. The Iraqi people will determine the future of Iraq and the United States will continue to support their efforts for a peaceful, secure, free, and prosperous nation," he said.
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