From the Oval Office, where George W. Bush first announced the invasion that would come to define his presidency, Obama addressed millions who were divided over the war in his country and around the world. He said the United States "has paid a huge price" to give Iraqis the chance to shape their future - a price that now includes more than 4,400 dead, tens of thousands of troops wounded and hundreds of billions of dollars spent since March 2003.
In a telling sign of the domestic troubles weighing on the United States and his own presidency, Obama turned much of the emphasis in a major war address to the dire state of U.S. joblessness.
In his remarks of slightly less than 20 minutes, only his second address from the Oval Office, Obama looked directly into the TV camera, hands clasped in front of him on his desk, family photos and the U.S. and presidential flags behind him.
Even as he turns control of the war over to the Iraqis - and trying to cap one of the most divisive chapters in recent American history - Obama is escalating the conflict in Afghanistan. He pledged anew that the United States would keep up the fight in that war, the longest since Vietnam.
And in Iraq, for all the finality of Obama's remarks, the war is not over. More Americans are likely to die. The country is plagued by violence and political instability, and Iraqis struggle with constant shortages of electricity and water.
Obama is keeping up to 50,000 troops in Iraq for support and counterterrorism training, and the last forces are not due to leave until the end of 2011 at the latest.
As the commander in chief over a war he opposed, Obama took pains to thank troops for their sacrifice but made clear he saw the day as more the marking of a mistake ended than a mission accomplished. He spoke of strained relations with allies, anger at home and the heaviest of wartime tolls.
"We have met our responsibility," Obama said. "Now it is time to turn the page."
To underscore his point, Obama said he had telephoned called Bush, whom he had taunted so often in the 2008 campaign, and he prominently praised the former Republican president in the heart of his speech.
"It's well known that he and I disagreed about the war from its outset," Obama said. "Yet no one could doubt President Bush's support for our troops, or his love of country and commitment to our security."
In a post-Sept. 11, 2001, world, the Iraq war began with bipartisan congressional backing - based on what turned out to be flawed intelligence - over what Bush called a "grave danger" to the world posed by Saddam Hussein.
Now, Iraq is in political turmoil, its leaders unable to form a new government long after March elections that left no clear winner. The uncertainty has left an opening for insurgents to pound Iraqi security forces, hardly the conditions the U.S. envisioned for this transition deadline, which Obama announced 18 months ago.
Obama pressed Iraq's leaders anew, saying it was time to show urgency and be accountable.
Obama sought both to assure his own nation that the war was finally winding down and yet also promise Iraq and those watching across the Middle East that the U.S. was not simply walking away.
"Our combat mission is ending," he said, "but our commitment to Iraq's future is not."