“I have come to speak to you about how the war in Iraq will end,” President Obama told Marines gathered at Fort Lejeune, N.C., on Friday.

Obama told the military audience and the nation he will pull out all U.S. combat troops over the next 18 months: “Let me say this as plainly as I can: by August 31, 2010, our combat mission in Iraq will end.”

This means the bulk of the 142,000 U.S. troops now in Iraq — administration officials put the number to be pulled out at roughly 92,000 to 107,000 — will be home by the end of next August.

Obama said “a transitional force” of 35,000 to 50,000 U.S. troops would remain after that to carry out training, equipping, and advising Iraqi security forces; counter-terrorism missions; and protecting U.S. civilian and military personnel.

But he flatly declared his intention to comply with the full withdrawal specified in the U.S.-Iraq status of forces agreement. “I intend to remove all U.S. troops from Iraq by the end of 2011,” he said.

This is a huge victory for all those in our country who have marched, lobbied, written letters, made phone calls and turned out the vote — to end the Iraq war, bring the troops home and turn our country’s foreign policy towards peace and international cooperation. Of course, we will have to continue to make our voices heard, to ensure that these intentions are carried out.

Obama spoke of “a critical recognition that the long-term solution in Iraq must be political — not military,” and that “the most important decisions that have to be made about Iraq’s future must now be made by Iraqis.”

He said the U.S. would turn from military combat to two other strategies. One is “sustained diplomacy on behalf of a more peaceful and prosperous Iraq.” This, he said, will include working with the United Nations to support Iraqi self-governance, and providing assistance to help the millions of Iraqis displaced by the war.

The second strategy the president outlined is “comprehensive American engagement across the region,” including Iran, Syria and the Israeli-Palestinian crisis.

This is an approach that the overwhelming majority of Americans and the people of the world have been yearning for.

It will require rethinking the role of the United States in the world.

Our government will have to break with the disastrous Cold War policies of the past. This means no longer propping up dictatorships and sprinkling military bases and nuclear weaponry around the globe. It means ending the dominance of reactionary oil interests, here and abroad, in our foreign policy, by redirecting our economy toward alternative energy sources.

It means adopting political, economic and social foreign policies that promote de-nuclearization and demilitarization, labor rights, grassroots economic and social development and culture, and real democracy — not the phony kind trumpeted by previous administrations.