WASHINGTON — John Edwards, who has challenged the Democratic presidential field to push for an end to the Iraq war, is not seeking to disengage completely from the region, or even from Iraq itself.

In a major essay published yesterday in Foreign Affairs, the former North Carolina senator writes that if he wins the presidency, he will aim to retain “sufficient forces in the region to prevent genocide, a regional spillover of the civil war, or the establishment of an Al Qaeda safe haven.” He calls for some forces to remain inside the international zone in the center of Baghdad to protect the American Embassy, and “quick reaction forces” to be stationed in Kuwait, as well as a continued naval presence in the Persian Gulf.

Such specific proposals place him much closer to his more hawkish rivals for the Democratic presidential nomination, especially Senator Clinton. The New York senator has said America should redeploy some of its troops to the Kurdish northern provinces. Senator Obama, a Democrat of Illinois, also has said America should retain enough troops to halt widespread killings, should Shiites continue the ethnic cleansing briefly interrupted by the current military surge.

Mr. Edwards, who as a senator was one of the Iraq war’s most vocal supporters from either party, has positioned himself as the outsider most in tune with the economic populism and anti-war sentiment of the Democratic Party’s Internet base. Yet his essay for the elite Foreign Affairs has him casting his presidency in a more centrist light.

On Iran, Mr. Edwards backs away from the position he elaborated earlier this year in an interview with the magazine American Prospect, in which he said he was unsure whether America should keep as an option on the table bombing the country’s nuclear reactors.

“With a threat so serious, no U.S. president should take any option off the table — diplomacy, sanctions, engagement, or even military force,” he writes. “When we say something is unacceptable, however, we must mean it, and that requires developing a strategy that delivers results, not just rhetoric. Instead of saber rattling about military action, we should employ an effective combination of carrots and sticks.”

Mr. Edwards argues for direct engagement with Iran on nuclear issues. “Such diplomacy is not a gift, nor is it a concession. The current administration recently managed to have one single-issue meeting with Iran to discuss Iraq,” he writes. “It simply makes no sense for the administration to engage Iran on this subject alone and avoid one as consequential as nuclear proliferation.”

The Bush administration has made Iran’s resuspension of uranium enrichment, a condition the country agreed to in 2004, a precondition for direct negotiation on nuclear issues.

The former senator’s biggest new idea is to create a new Marshall Corps, named after a former general and secretary of state, George Marshall, of 10,000 civilian specialists to assist in humanitarian reconstruction.

“In the coming years, we will most likely see an increasing need to stabilize weak and failing states and provide humanitarian assistance to the victims of disasters across the world,” he writes.

But he said that too often the American military serves as the front line aid agency for pending disasters. “The military lacks many of the resources that are required to conduct these missions successfully,” he writes.