WASHINGTON — If Senator Clinton can best Senator Obama in today’s round of primaries and caucuses and go on to capture the White House, a co-author of the surge strategy in Iraq says he is convinced she would hold off on authorizing a large-scale immediate withdrawal of American soldiers from Iraq.

In a weekend interview, a retired four-star general, Jack Keane, said that when he briefed Mrs. Clinton in late 2006 and January 2007 on the counteroffensive strategy known as the surge, she “generally supported the surge strategy in the sense she wanted it to succeed but she was skeptical about its chances.”

The Obama campaign yesterday seized on the general’s comments after they appeared in an article on The New York Sun’s Web site, with the chief spokesman, William Burton, issuing a statement saying: “Senator Clinton needs to explain to the American people what she said to the architect of George Bush’s surge that made him think she wouldn’t end the war.”

Mr. Keane is in a position to know Mrs. Clinton, having worked informally with her since 2001, when he was vice chief of staff for the Army. Early last year, the Clinton team even asked the retired general to become a formal adviser to the campaign on military issues, a request Mr. Keane declined, as he has done when asked by other candidates.

Mr. Keane nevertheless said he holds the former first lady in high esteem.

“Senator Clinton is very knowledgeable about national security and is probably going to be strong on defense,” he said. “I have no doubts whatsoever that if she were president in January ’09 she would not act irresponsibly and issue orders to conduct an immediate withdrawal from Iraq, regardless of the consequences, and squander the gains that have been made.” Mr. Keane added that he could not imagine any president in the White House making that kind of decision.

The senator’s campaign differed with that assessment. “Senator Clinton speaks for herself on her plans to end the Iraq war,” the campaign’s communication director, Howard Wolfson, said Sunday. “She has said she will end the war the right way, swiftly and responsibly, and beginning within 60 days of taking office.”

Indeed, Mrs. Clinton’s Web site features her plan to “begin ending this war — not next year, not next month — but today.” She has pledged to call together her military and national security team to draw up plans to “bring our troops home starting with the first 60 days of her Administration.”

Throughout 2007, Mrs. Clinton has sought to distance herself from her vote in 2002 to authorize the use of force in Iraq, a resolution that she says was intended to create leverage for negotiations with Iraq at the U.N. Security Council, but was widely considered by almost all other observers as a resolution authorizing the 2003 invasion of Iraq.

Also, Mrs. Clinton has played up her national security judgment and experience. Over the weekend, the campaign released a television ad depicting a late-night phone call to the White House denoting an unspecific national security crisis. A narrator says: “It’s 3 a.m., and your children are safe and asleep, but there’s a phone in the White House and it’s ringing.” The implication is that Mrs. Clinton would be better able to deal with the crisis than her opponents.

Over the summer, Mrs. Clinton also promised America would commit troops to protecting the pro-American Kurdish region of northern Iraq, and she was one of the first in her party to acknowledge the security gains of the surge. Like Mr. Obama, Mrs. Clinton says she supports keeping a residual force in Iraq, but has opposed the construction of permanent bases.

In September, when General Petraeus testified before the Senate Armed Services Committee, the former first lady made headlines when she said his optimistic assessment of security gains required “the willing suspension of disbelief.” The remark spurred the Republican front-runner at the time, Mayor Giuliani, to take out an ad in the New York Times lambasting her. It also drew cheers from Democratic Party’s base, which had rallied that week behind moveon.org and its ad in the Times labeling the commander of multi-national forces in Iraq “General Betray-us.” Mr. Keane’s collaborator on the counteroffensive strategy in Iraq, an American Enterprise Institute scholar, Fred Kagan, yesterday said that he thought the direction of Mrs. Clinton’s campaigning would make it very difficult for her to reverse course on Iraq.

“Hillary’s inclinations may well be sound when she comes into office, she may well not want to do something to undermine progress in an important theater,” Mr. Kagan said. “But increasingly the external constraints on her ability to act responsibly seem to be growing in part as a result of the extremist rhetoric that she herself has been adopting.”

Kenneth Pollack, a Persian Gulf specialist who worked for the Clinton White House, and who has become a proponent of the military surge in Iraq since leaving government, said yesterday: “I don’t know what she would do as president. But all of my experience with her when she was first lady is that this is a woman who would put our nation’s interests first and any campaign promises a distant second.”

With Michael O’Hanlon, a fellow scholar at the Brookings Institution, Mr. Pollack co-wrote an op-ed article for the Times over the summer noting military and security gains in Iraq at a time when most of their fellow Democrats were insisting that such good news being trumpeted by the Pentagon was a mirage.

Mr. O’Hanlon yesterday said Mrs. Clinton in 2003 and 2004 was at least critical of the surge strategy but not in favor of withdrawal. “When I spoke to Senator Clinton, which was shortly after the invasion and well before the surge, this is a broad and somewhat vague characterization, but early on she was making some of the critiques McCain was,” he said. “The kinds of plans for getting out were not part of the discussions I had with her.”