President Obama yesterday declared he will end combat operations in Iraq within 18 months, and last night said the U.S. has lost focus on its goals in Afghanistan.

He said his administration must set clear policy objectives for the fight in Afghanistan before coming up with a plan to bring U.S. troops home.

"Until we have a clear strategy, we're not going to have a clear exit strategy," Obama said on public television's "NewsHour With Jim Lehrer."

"My goal is to get U.S. troops home as quickly as possible without leaving a situation that allows for potential terrorist attacks against the United States."

In consigning the Iraq war to history, Obama also said in a separate address that he will open a new era of diplomacy in the Middle East.

"Let me say this as plainly as I can: By Aug. 31, 2010, our combat mission in Iraq will end," he told Marines at Camp Lejeune, N.C., who are about to deploy by the thousands to Afghanistan.

Even so, Obama will leave the bulk of troops in place this year, contrary to hopes of Democratic leaders for a speedier pullout. And after combat forces withdraw, 35,000 to 50,000 will stay behind for an additional 1 1/2 years of support and counterterrorism duties.

Last night, he said there's been a "sense of drift in the mission in Afghanistan" and the U.S. must work with allies to help the country develop economically and not be a safe haven for terrorists.

"We've been thinking very militarily, but we haven't been as effective in thinking diplomatically, we haven't been thinking effectively around the development side of the equation," he said. "You know, what are we doing to replace poppy crops for Afghans that allow them to support themselves?"

The U.S. would be "further along" in dealing with such issues in Afghanistan if the Bush administration had stayed more focused on the region, Obama said.

"But, you know, that's history," he said. "We now have to move forward. It's my job to come up with the best possible approach given some of the mistakes that have been made, and the fact that the situation right now has deteriorated badly in Afghanistan."

POLICY SOLIDARITY

Defense Secretary Robert Gates and Adm. Mike Mullen, chairman of the Joint Chiefs of Staff, flanked Obama at the announcement at Camp Lejeune. It was a symbolic statement that top military advisers are on board with a strategy some had openly questioned before Obama's inauguration.

More than five years have passed since Bush declared the end of major combat operations in Iraq, a statement that proved false as insurgency and sectarian violence seethed up in Iraq.

Obama did not claim a mission accomplished. Instead, he suggested America has done what it could.

"What we will not do is let the pursuit of the perfect stand in the way of achievable goals," he said. "We cannot rid Iraq of all who oppose America or sympathize with our adversaries. We cannot police Iraq's streets until they are completely safe, nor stay until Iraq's union is perfected."

He said: "America's men and women in uniform have fought block by block, province by province, year after year, to give the Iraqis this chance to choose a better future. Now we must ask the Iraqi people to seize it."

Obama's promise to pull home the last of the U.S. troops by the end of 2011 is in accord with a deal that Iraq's government signed with former President George W. Bush.

Obama applauded the armed forces for their successes in Iraq, where violence in many parts of the country is significantly down. More than 4,250 Americans have been killed in Iraq.

"We will leave the Iraqi people with a hard-earned opportunity to live a better life. That is your achievement. That is the prospect that you have made possible," he said to the military members.

Obama is accelerating the end of the war by withdrawing roughly 100,000 troops by the summer of 2010.

Obama said to the men and women in uniform before him: "I promise you that I will only send you into harm's way when it is absolutely necessary."

MOVING 'FORWARD'

Obama said one of his objectives when he attends an April meeting of the North Atlantic Treaty Organization will be to discuss how to "move the ball forward" in Afghanistan. "Afghanistan is not a U.S. mission, it's a NATO mission," Obama said.

The president last week decided to send 17,000 additional U.S. combat and support troops to Afghanistan. In a statement, he said the deployment is "necessary to stabilize a deteriorating situation in Afghanistan, which has not received the strategic attention, direction and resources it urgently requires."

The U.S. has about 38,000 personnel in Afghanistan, and there are about 32,000 troops there from other NATO countries.

When asked on "NewsHour" whether the mission in Iraq can be viewed as successful, Obama said the U.S. military "unequivocally succeeded in every mission given to them." The problem, he said, was lack of competent civilian oversight.

"I don't think that we can rightly say that the strategy cooked up by our civilian leadership, with respect to either going in in the first place or how the war was managed, was a success," Obama said.

Obama defended his plan in Iraq when asked about comments by Democrats, including Senate Majority Leader Harry Reid of Nevada, that the withdrawal isn't as sweeping as they expected.

"Well, what I would say is that they maybe weren't paying attention to what I said during the campaign," Obama said. "I said that we were going to take 16 months to withdraw our combat troops from Iraq. We are now taking 18 months rather than 16."

Obama also said he previously had made the commitment to keep a residual force in Iraq.

"Everything that I said I would do during the campaign I am now doing," he said. "Obviously, because of consultation with commanders on the ground, something I also said we would do, there are some modifications to the plan."