Even as Obama was nominating Sen. John F. Kerry (D-Mass.) as secretary of State on Friday, the possible selection of Hagel, a Republican who served two terms as a U.S. senator from Nebraska, drew intensifying crossfire from influential pro-Israel groups, Iran hawks and the gay rights lobby.
Obama backed down Dec. 13 on his first choice for secretary of State, United Nations Ambassador Susan Rice, after she faced harsh GOP opposition for her comments about the attack on a U.S. mission in Benghazi, Libya.
Democratic foreign policy leaders and congressional allies privately criticized the White House's handling of the nominations, which some say follows a pattern of sloppy management of personnel selections. They worry that another retreat could embolden Republicans to challenge future nominations.
A top White House advisor said Friday that Obama was still considering Hagel, but that he was also looking at Michele Flournoy, who was Pentagon undersecretary for policy in Obama's first term, and Ashton Carter, the current deputy secretary, the Defense Department's second-ranking position.
The advisor said Obama hadn't settled on Hagel and was not deterred by the criticism now. But with Rice out of the running for a Cabinet post, Obama may seek diversity among his new team and give greater weight to nominating Flournoy as the first woman to run the Pentagon.
As criticism mounted, Hagel broke his silence Friday by apologizing for his comments in 1998, when he denigrated a nominee to be ambassador to Luxembourg as "openly, aggressively gay." In a statement, Hagel called his remarks "insensitive," and said "they do not reflect the totality of my public record."
Also Friday, Rep. Eliot L. Engel (D-N.Y.), who will be the ranking Democrat on the House Foreign Affairs Committee in the next Congress, complained in a C-SPAN interview about Hagel's reference to the "Jewish lobby" in a book by former U.S. peace negotiator Aaron David Miller.
"It shows at the very best a lack of sensitivity, at the very worst perhaps a prejudice," Engel said. "And I'm concerned about it. I'm concerned about the nomination."
A Hagel nomination appealed to White House aides after the bitter election campaign because it would show bipartisanship, and might help win congressional support for expected cuts to the defense budget.
But the Nebraskan moderate has little support in the conservative Republican Senate caucus. And the pro-Israel and gay rights groups that oppose him have strong influence in the Democratic Party.
"Despite his two Purple Hearts, I'm not sure how much support he has within the Democratic caucus," said Jim Manley, a former aide to Senate Majority Leader Harry Reid (D-Nev.).
Hagel's views on Israel have sparked the most controversy. Such groups as the Anti-Defamation League and the American Jewish Committee have begun publicly condemning some of his statements about the Jewish state, his votes against sanctions on Iran, and his calls for the United States to be more even-handed in negotiations between Israel and the Palestinians. They worry he would resist going to war to stop Iran from gaining a nuclear weapon.
Other groups, including the liberal pro-Israel J Street organization, and prominent foreign policy experts — including Brent Scowcroft, national security advisor to President George H.W. Bush, and Zbigniew Brzezinski, national security advisor to President Carter — have rallied to his side.
Flournoy helped Obama craft his decision to withdraw U.S. troops from Iraq, and to shift security responsibility to Afghan army and police units by the end of 2014.
But Flournoy has few close ties to lawmakers who will control Pentagon appropriations as the defense budget shrinks, according to an administration official, who spoke anonymously because Flournoy has not been nominated.
"She has the 'no drama' competence that this White House likes, but not the political pull with the Hill that will be important," the official said.
Ashton Carter, who has served in Defense Department policy jobs in several Democratic administrations, is a proliferation expert and has years of experience running the Pentagon's massive weapons acquisition process.
Christi Parsons in the Washington bureau contributed to this report.