|WASHINGTON — In his effusive endorsement of Chuck Hagel as his choice for secretary of defense on Monday, President Obama set in motion a White House campaign that officials predict will overcome weeks of accusations that the Republican former senator from Nebraska is anti-Israel, antigay and soft on Iran.
The president extolled Mr. Hagel’s record as a decorated veteran of the Vietnam War, saying that he was “the leader that our troops deserve.” He described how Mr. Hagel once saved his brother, who was fighting alongside him, after he was wounded by a mine.
“With Chuck, our troops will always know, just as Sergeant Hagel was there for his own brother, Secretary Hagel will be there for you,” said Mr. Obama, who was flanked by Mr. Hagel and the departing defense secretary, Leon E. Panetta, at the White House ceremony.
“Maybe most importantly,” the president continued, “Chuck knows that war is not an abstraction. He understands that sending young Americans to fight and bleed in the dirt and mud, that’s something we do only when it’s absolutely necessary.”
The president’s message seemed intended in particular for the conservative critics of Mr. Hagel, including Senator John McCain of Arizona, who have warned that he will face a bruising confirmation battle. White House officials said that Republicans, whatever their policy disagreements, would find it difficult to vote against an acknowledged war hero.
Mr. Obama’s announcement was part of a carefully calibrated White House strategy that has included reaching out to pro-Israel lobbying groups, with a goal of wearing down the resistance to Mr. Hagel that erupted as soon as he emerged last month as a front-runner for the Pentagon post.
Conservative and Jewish groups reiterated their concerns on Monday that Mr. Hagel has opposed sanctions on Iran, failed to support Israel, and has advocated engaging with Hamas and Hezbollah. They want him to explain why he once referred to pro-Israel lobbying groups as “the Jewish lobby,” a phrase they said was hurtful to Jews.
Still, it was not clear how hard they will fight to block Mr. Hagel, now that the president has nominated him. “We’re not in the opposition camp, we’re in the concerned camp,” said David Harris, the executive director of the American Jewish Committee, a centrist Jewish group. “We’re going to count on the Senate to examine, as it must, key issues of concern."
Republican and some Democratic senators predict Mr. Hagel will still face tough questions about his views on Israel, Iran, and negotiating with Islamic militants. He has also faced criticism from gay rights organizations because of remarks he made 14 years ago — for which he has since apologized — about an openly gay diplomat.
In a statement, Mr. McCain, a Vietnam veteran like Mr. Hagel who serves on the Senate Armed Services Committee, said, “I have serious concerns about positions Senator Hagel has taken on a range of critical national security issues in recent years.” But he added, “Chuck Hagel served our nation with honor in Vietnam.”
The White House is working behind the scenes to mollify other potential critics. Administration officials said Mr. Obama’s chief of staff, Jacob J. Lew, called Howard Kohr, the executive director of the American Israel Public Affairs Committee, one of the most influential pro-Israel lobbying groups.
A spokesman for Aipac, Marshall Wittmann, said the group did not take a position on presidential nominations.
Mr. Harris, of the American Jewish Committee, said Iran topped his list of concerns about Mr. Hagel because the senator voted against unilateral American sanctions against the Iranian government over its nuclear program and had argued against using the threat of military force to prevent Tehran from obtaining a nuclear weapon.
Abraham H. Foxman, the national director of the Anti-Defamation League, said the senators should challenge Mr. Hagel on his positions on Israel and Iran, which he said were “so out of sync” with those of the president.
On Monday, White House officials rounded up examples of what they said showed the hypocrisy of the senator’s critics. In e-mails to reporters, they noted that Dick Cheney, the Republican former vice president; television news networks; and The Washington Times had all used the phrase “Jewish lobby” without generating a furor.
Mr. Hagel has said positive things about Israel, too, and White House officials were quick to note them. While Mr. McCain expressed “serious concerns,” officials noted that in 2006, he said Mr. Hagel would make “a great secretary of state.”
The biggest gun in the White House’s armory, aside from the president, is Mr. Hagel himself. And he served notice that he would defend himself vigorously.
While diplomatic in his remarks at the White House, he gave an interview to a Nebraska newspaper, published Monday, in which he complained that he had been “hanging out there in no man’s land, unable to respond to charges, falsehoods, and distortions.”
“The distortions of my record have been astounding,” Mr. Hagel told The Lincoln Journal Star. He said there was “not one shred of evidence that I’m anti-Israel, not one vote that matters that hurt Israel.”
Mr. Obama’s rapport with Mr. Hagel goes back to their days in the Senate. In July 2008, Mr. Hagel and Senator Jack Reed, Democrat of Rhode Island, accompanied Mr. Obama on a trip to Afghanistan that burnished Mr. Obama’s foreign policy credentials as the Democratic nominee.
Like the president, Mr. Hagel is suspicious of a lingering American military presence in Afghanistan, and would most likely be comfortable with a more rapid drawdown of American troops after responsibility for security is turned over to the Afghans at the end of 2014.
Mr. Obama referred obliquely to the controversy around Mr. Hagel, saying soldiers in the field were far away from the politics of Washington, but should not be handicapped by it.
He urged the Senate to act promptly on Mr. Hagel’s nomination, adding, “When it comes to national security, we don’t like to leave a lot of gaps.”
If confirmed, he said, Mr. Hagel, 66, would be the first former enlisted man and the first Vietnam veteran to serve as defense secretary, and one of the few ever wounded in war.
John Nagl, a retired Army officer and professor of history at the Naval Academy, said Mr. Hagel talked of his combat credentials in addressing a class he was teaching at West Point. “He said: ‘I was that 19-year-old rifleman. Look me in the eye and tell me that if you send a kid to get killed, it will be for a mission that matters.’ ”
“He’ll be a voice for G.I. Joe, and that’s a very valuable thing,” Mr. Nagl said.