Continued from page 1

With all combat troops out of Iraq and most scheduled to leave Afghanistan by next year, Mr. Hagel would have a chance to put his imprint on the force and an unwieldy procurement culture that produces expensive weapon systems.

“I think Sen. Hagel is an excellent choice to head the Department of Defense,” said retired Army Col. Peter Mansoor, a key command adviser in Iraq during the 2007 troop surge. “He is well-versed in Washington politics, and having seen the sharp end of combat in Vietnam gives him a unique perspective on policies that could very well put America’s young men and women into harm’s way.”

Army Times, an independent newspaper, published an article about Mr. Hagel’s service as an Army enlisted man who was awarded two Purple Hearts in Vietnam. The newspaper has a following among active-duty and retired soldiers. “A SECDEF who doesn’t want to go to war?” one reader commented. “What was Obama thinking? Maybe now the U.S. will develop a foreign policy that doesn’t list war as the first option.”

Some residual distrust about Mr. Obama as commander in chief remains among the top brass.

Retired Army Gen. Stanley A. McChrystal, who resigned his Afghanistan command after remarks in a magazine article, told The New York Times this month: “With the start of the Obama administration, we had a financial crisis, we had a new administration, and yet we had this compressed decision-making timeline on Afghanistan before people had been able to mature relationships and trust to go at this as effectively as I think they would have liked to.”

Asked whether trust improved, he said, “I think it’s a problem that needs to be worked at.”

Mrs. Flournoy earned that trust, military sources say. She served three years as defense policy chief before resigning to spend more time with her family. With Kurt M. Campbell, an assistant secretary of state, Mrs. Flournoy also co-founded the Center for a New American Security, where she still serves on the board.