OBAMA

WASHINGTON — President-elect Barack Obama has decided to keep Defense Secretary Robert M. Gates in his post, a show of bipartisan continuity in a time of war that will be the first time a Pentagon chief has been carried over from a president of a different party, Democrats close to the transition said Tuesday.

Mr. Obama’s advisers were nearing a formal agreement with Mr. Gates to stay on for perhaps a year, the Democrats said, and they expected to announce the decision as early as next week, along with other choices for the national security team. The two sides have been working out details on how Mr. Gates would wield authority in a new administration.

The move will give the new president a defense secretary with support on both sides of the aisle in Congress, as well as experience with foreign leaders around the world and respect among the senior military officer corps. But two years after President Bush picked him to lead the armed forces, Mr. Gates will now have to pivot from serving the commander in chief who started the Iraq war to serving one who has promised to end it.

In deciding to ask Mr. Gates to stay, Mr. Obama put aside concerns that he would send a jarring signal after a political campaign in which he made opposition to the war his signature issue in the early days. Some Democrats who have advised his campaign quietly complained that he was undercutting his own message and risked alienating war critics who formed his initial base of support, especially after tapping his primary rival, Senator Hillary Rodham Clinton, for secretary of state.

But advisers argued that Mr. Gates was a practical public servant who was also interested in drawing down troops in Iraq when conditions allow.

“From our point of view, it looks pretty damn good because of continuity and stability,” said an Obama adviser, who insisted on anonymity to discuss confidential deliberations. “And I don’t think there are any ideological problems.”

Associates said Mr. Gates was torn between a desire to retire to a home in Washington State and a sense of duty as the military faces the daunting challenges of reducing forces in Iraq and increasing them in Afghanistan.

As Mr. Obama moved closer to assembling his national security team Tuesday, he lost a top candidate for director of the Central Intelligence Agency. John O. Brennan, an agency veteran who was widely seen as the front-runner, withdrew from consideration amid concerns that he was linked to controversial intelligence programs authorized by Mr. Bush.

In a letter to Mr. Obama, Mr. Brennan said he did not want those concerns to be a “distraction” for the incoming administration. At the same time, he vigorously defended his record and called himself a “strong opponent” of the harsh interrogation methods the agency used in recent years, including waterboarding, the practice of making a suspect experience the sensation of drowning.

The developments came as Mr. Obama prepared to begin unveiling his national security team after the long Thanksgiving weekend. Besides formally announcing his nomination of Mrs. Clinton as secretary of state, Mr. Obama was expected to appoint Gen. James L. Jones, a retired Marine commandant and NATO supreme commander, as his national security adviser.

Other front-runners have emerged in recent days, including Adm. Dennis Blair, retired from the Navy, for director of national intelligence; Susan E. Rice, a former assistant secretary of state, for ambassador to the United Nations; James B. Steinberg, a former deputy national security adviser, for deputy secretary of state; and Thomas E. Donilon, a former chief of staff at the State Department, for deputy national security adviser.

The team is shaping up as one of experience more than change, figures with long résumés but at times conflicting backgrounds. Nothing reflects that more than keeping a Republican-appointed defense secretary. Although Presidents Lyndon B. Johnson and Gerald R. Ford made no change at the top of the Pentagon when they took office, no president has kept a defense secretary from a predecessor in another party, Donald Ritchie, a Senate historian, said.

Mr. Gates, who served as C.I.A. director under the first President Bush, would not have to be reconfirmed by the Senate. The prospect of retaining him generated praise from the military establishment and Capitol Hill, where he is viewed as a pragmatist who turned the Pentagon around after the tumultuous tenure of Donald H. Rumsfeld.