WASHINGTON — A senior military adviser to Senator Obama says Iraqi national elections, scheduled for late 2009, would be possible under the Democratic presidential candidate’s plan to withdraw American combat brigades from Iraq.

“Iraqi elections are a very useful thing,” Richard Danzig said yesterday at a press conference at which three national security experts gave testimonials on behalf of the junior senator from Illinois. Mr. Danzig, a former secretary of the Navy under President Clinton, added that Mr. Obama’s plan to withdraw one or two combat brigades a month over 16 months “would fully be able to protect those elections and make sure there were enough troops on the ground to make sure it goes forward.” The adviser said later that he believed progress in training an Iraqi national army and other local Iraqi forces meant that fewer American troops would be needed than in 2005, when coalition forces fanned out across Iraqi cities and towns to protect voters from Al Qaeda and other terrorists.

Should it go forward, the 2009 vote would mark the fourth consecutive round of national elections for Iraq, following two national elections for parliament and a referendum on the constitution. Provincial elections, initially scheduled for this month, hit a snag after the Iraqi presidency council vetoed a plan last month from the parliament. New elections could result in some of the confessional parties being forced to reform or being unseated by newer parties committed to national reconciliation and unity.

The Democratic presidential candidates have taken careful positions on Iraq. While Senator Clinton and Mr. Obama have pledged to end the war and begin a withdrawal from Iraq after taking office, both have offered caveats that they would be open to basing their positions on facts on the ground in January 2009.

A senior foreign policy adviser to Mr. Obama, Samantha Power, said on BBC’s “HARDtalk” last week that the Illinois senator’s withdrawal plan would likely change to accommodate the situation on the ground in Iraq. (Ms. Power resigned Friday over comments she made about Mrs. Clinton.) The Clinton campaign has pointed to this interview to suggest that Mr. Obama does not intend to end the war immediately. The Obama campaign has countered by sending around a March 3 New York Sun story in which one of the architects of the surge strategy for Iraq, a retired Army general, Jack Keane, said he had no doubt that Mrs. Clinton would not immediately withdraw troops and relinquish military gains achieved in Iraq in the last 14 months.

“The key factor in whether or not there are elections in Iraq is whether there is consensus among the factions that they have something to gain in holding elections,” the national security director for Mrs. Clinton’s campaign, Lee Feinstein, said yesterday. “The provincial elections originally slated for October, for example, were vetoed by the presidency council because no such consensus existed, and U.S. troops were at or near record levels at that time.”

Mr. Feinstein added: “If politics in Iraq have progressed to the point where presidential elections are able to be held on schedule, then there ought not to be a need for large numbers of troops. Nonetheless, security is obviously important, and even where you get a consensus that enables elections, there could be spoilers, and the residual forces, including forces to counter Al Qaeda, will be sufficient. Moreover, Senator Clinton has always said that she will use this time to build pressure on Iraqis of all stripes to pursue national reconciliation.”

It is too early to estimate the troop levels necessary for the 2009 Iraqi national elections, Anthony Cordesman, of the Center for Strategic and International Studies, said.

But Mr. Cordesman, who holds the Arleigh A. Burke chair in strategy at CSIS, said the level of intra-Shiite tensions in the south, the cooperation and progress of the Iraqi national army, and the ability of Iraqi and coalition forces to defeat Al Qaeda in Iraq would determine the American presence for the 2009 elections. “For anyone to make more than speculation at this point is to issue a statement that can’t have substantive meaning,” he said.

Mr. Cordesman added that he, like Mr. Danzig, expected that a lot of security for the 2009 elections would fall on Iraqi, not coalition, forces.