Camp Lejeune, N.C. ? President Barack Obama consigned the Iraq war to history Friday, declaring he will end combat operations within 18 months and open a new era of diplomacy in the Middle East.

“Let me say this as plainly as I can: By August 31, 2010, our combat mission in Iraq will end,” Obama told Marines who are about to deploy by the thousands to the other war front, 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 year and half of support and counterterrorism duties.

Just six weeks into office, Obama used blunt terms and a promise to write the last chapter of a war that began six years ago. It has cost more in lives, money and national stamina than ever envisioned.

Like Dwight Eisenhower and Richard Nixon before him, Obama came into office with an inherited war he pledged to end without delay. Eisenhower did, in Korea. Nixon didn’t, in Vietnam. Obama says he will.

“Iraq’s future is now its own responsibility,” Obama said.

Defense Secretary Robert Gates and Adm. Mike Mullen, chairman of the Joint Chiefs of Staff, flanked Obama during the announcement. 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 sectarian violence brought Iraq to the brink of disaster.

Obama did not claim a mission accomplished. Instead, he suggested America accomplished the mission as best 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.”

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

Obama was moving to fulfill in large measure the defining promise of his campaign — to end combat operations within 16 months of taking office. He’s doing it in 19 months instead, and the drawdown will be backloaded to provide security for Iraqi elections late this year.