"The hard truth is we have not seen the end of American sacrifice in Iraq," the president said in a speech to the national convention of the Disabled American Veterans. "But make no mistake, our commitment in Iraq is changing - from a military effort led by our troops to a civilian effort led by our diplomats."
A transitional force of 50,000 troops will remain, down from the peak of 160,000 in 2007. Their mission will be to train and advise Iraqi security forces, protect U.S. civilians, manage the chain of supplies and equipment out of Iraq and conduct counterterrorism operations.
Those soldiers and Marines will remain in harm's way and will be likely to engage at times in some form of fighting. Iraqi commanders will be able to ask the U.S. for front-line help.
All American troops are to leave Iraq by the end of next year, as mandated under an agreement negotiated before Obama took office, between the Iraqis and President George W. Bush.
Obama's speech Monday was the first of many, with appearances planned throughout the month by the president, Vice President Joe Biden and other administration officials. The schedule reflects a White House eager, with pivotal congressional elections approaching, for achievements to tout, especially in areas with the emotional significance of the Iraq war.
Obama's campaign pledge to oversee a speedy conclusion to the U.S. fighting was the promise that most defined his presidential campaign, and it brought him significant support.
Actually, while running for the White House, he said he would remove one or two brigades a month from Iraq to achieve an end to combat operations within 16 months of taking office. Instead, shortly after becoming president, Obama settled on a slower plan, to remove all combat troops within 19 months, and not at the pace of one brigade per month but on a more backloaded timetable.
Those were concessions to the military that disappointed Obama's anti-war base of support.
Obama's celebratory rhetoric on Monday brushed past some of the more grim realities in today's Iraq.
Leaders there remain at a political impasse that has prevented the formation of a new government for the nearly five months since parliamentary elections did not produce a clear winner.
In a reminder of Iraq's fragility, two bombings and a drive-by shooting killed eight people there Monday just hours before Obama spoke.
With such attacks remaining a daily occurrence, especially in Baghdad, questions persist about the readiness of Iraqi security forces to take over for the Americans and hold back insurgents.
Obama said, "Violence in Iraq continues to be near the lowest it's been in years," but figures released by Iraqi authorities over the weekend - dismissed by the U.S. military as too high - showed July to be the deadliest month for Iraqis in more than two years.
Frustration over the political deadlock has come on top of widespread Iraqi anger over the governments failure to improve basic services such as electricity and drinking water.
With billions of dollars already spent to improve electricity since the U.S.-led invasion in 2003, households in Baghdad continue to suffer lengthy power outages. That's a particularly sore subject with Iraqis since the summer months routinely see 115-degree days and buying electricity from privately owned neighborhood generators is beyond the reach of many.
Some longtime Iraq observers worry that the country's sectarian divisions could widen in the months ahead.
"Much of the violence has occurred because there is no government, because nobody knows what the future is," said Anthony Cordesman, a military analyst at the Center for Strategic and International Studies who has periodically advised top U.S. commanders in Baghdad.
However, military officials say that neither Iraqi political turmoil nor the continuing violence will change the departure plan. Adm. Mike Mullen, chairman of the Joint Chiefs of Staff, visited Iraq last week and came away confident that the switch to a fully advisory role can occur as planned, his spokesman said Monday.
Also, Cordesman said that if the Obama administration were to extend the combat mission beyond Aug. 31 or seek to renegotiate the December 2011 withdrawal, the U.S. would be seen by many Iraqis as reverting to the role of an occupier.
At the same time Obama has drawn down forces in Iraq, he has increased the U.S. commitment in Afghanistan, ordering a surge of 30,000 additional troops for the 9-year mission there.
Casualties are on the rise, causing some to argue the Afghanistan war should be ended quickly but others to question Obama's plan to begin winding it down as soon as next July. Critics say such a timetable will embolden the Taliban and other extremist groups in the region.
With debate continuing and war support low, the White House has launched a fresh effort to paint the U.S. goals in Afghanistan as modest: keeping the region from being a haven for terrorists.
"We face huge challenges in Afghanistan," Obama said Monday. "But it's important that the American people know that we are making progress and we're focused on goals that are clear and achievable."
The United States lost four troops in Iraq last month, and only one of those was in combat. July was the deadliest month of the war in Afghanistan, with 66 U.S. troops killed.
Speaking before a mostly friendly crowd of more than 2,500 disabled veterans, some in wheelchairs, others with lost limbs, Obama promised an all-out effort to support the nation's troops.
"Your country is going to take care of you when you come home," he said.
After the speech, he headlined a lunch to raise campaign cash for the Democratic National Committee, his latest stop in a summer fundraising sprint that also includes events in Chicago later this week.
--- Associated Press writers Hamid Ahmed and Hamza Hendawi in Baghdad, Shannon McCaffrey in Atlanta and Robert Burns and Anne Gearan in Washington contributed to this report.