Former Sen. Chuck Hagel’s path to confirmation as secretary of Defense will hinge to a tremendous degree on his performance at his Senate confirmation hearing, which promises to be a blockbuster, both those in favor and against his nomination agree.

Conservative Republicans, defense hawks and much of the pro-Israel community are girding for a fight, promising a strong lobbying effort to pressure moderate Republicans and Democrats to oppose the Nebraska Republican’s nomination, which was announced Monday by President Barack Obama.

“I think you’re going to see a multidimensional campaign to inform the American people and to inform senators about Chuck Hagel’s record and just how far out of the mainstream it is,” one Senate Republican aide said Sunday. Groups such as the Israel Project and the American Jewish Committee and commentators such as William Kristol of the Weekly Standard and former Bush administration official Dan Senor have all been active in denouncing Hagel’s qualifications and track record.

Hagel has alienated many in his party with his vocal criticism of the Bush administration’s management of the Iraq War, his support for engagement rather than sanctions against Iran and terrorist groups such as Hezbollah and his critique of what he once dubbed the “Jewish lobby.” In recent years he has endorsed Democratic candidates for federal office and serves on Obama’s intelligence advisory board.

While a handful of Republican senators have come out firmly against the nomination before the announcement — including GOP Whip John Cornyn of Texas, Lindsey Graham of South Carolina, Tom Coburn of Oklahoma, Dan Coats of Indiana, Roger Wicker of Mississippi and Ted Cruz of Texas — other Republicans as well as Senate Democrats have remained noncommittal. All cite the need to hear from Hagel directly about his past comments and positions.

“He’s certainly been outspoken in foreign policy and defense over the years,” Senate Minority Leader Mitch McConnell, R-Ky., said on ABC’s “This Week With George Stephanopoulos” on Sunday morning. “The question we’ll be answering if he’s the nominee is, do his views make sense for that particular job. I think he ought to be given a fair hearing, like any other nominee. And he will be.”

Republican Marco Rubio of Florida has also expressed skepticism about Hagel, but his spokesman, Alex Conant, said Monday that Rubio will not pre-judge the nomination.

“Senator Rubio hopes he will be able to meet with Senator Hagel prior to his confirmation vote,” Conant said. “We’ll have questions about some of Senator Hagel’s past positions, including sanctions on Iran and promoting democracy in Latin America.”

The focus of the anti-Hagel lobbying efforts is likely to center on more moderate Republicans such as Sens. Susan Collins of Maine and Bob Corker and Lamar Alexander, both of Tennessee, as well as other veteran GOP senators who served with and remain friends with Hagel. On the Democratic side, all eyes will be on a group of lawmakers known to be hawkish on Iran and staunch defenders of Israel, among them Sens. Charles E. Schumer and Kirsten Gillibrand of New York, Frank R. Lautenberg and Robert Menendez of New Jersey, Richard Blumenthal of Connecticut and Bob Casey of Pennsylvania.

With some in the GOP already threatening a hold, Democrats will likely need to get to 60 votes to move Hagel’s nomination through the Senate, meaning he’ll need to win over at least five Republicans.

One Senate Democratic aide said his boss was inclined to be supportive but would need to be convinced, given the criticism of Hagel that has garnered since his name was floated as a top contender for the post last month.

“He gets the benefit of the doubt by being President Obama’s choice and for having tried to make amends,” the aide said, “but he’s going to need to put on a real show over the next few weeks to prove he’s not the Israel-hating, gay-bashing villain that’s been portrayed these last few months” — an apt summary of where much of the Democratic rank and file is at this point.

Indeed, the attacks on Hagel, particularly in the conservative press, have been unrelenting over the past several weeks.

Much of the ire has been focused on what critics say have been his record of anti-Israel statements and votes, including his 2008 comments on the “Jewish lobby” and his failure to sign on to a 1999 letter to then-Russian President Boris Yeltsin — signed by all 99 other senators — condemning anti-Semitism in Russia.

Hagel backers retort that he always had a policy of not signing letters to foreign heads of state regarding their domestic policy and that he misspoke when he used the term “Jewish lobby.” He has also opposed attempts to sanction Iran and its proxies in the Middle East, which is at odds with a Congress that has been strongly supportive of increasingly tough measures to isolate Tehran and its allies.

That raises real questions, the Senate GOP aide said, as to how Hagel would perform at the helm of the Pentagon. “How will he advise the president on the ratcheting up of sanctions against Iran, on military planning vis-à-vis Iran, on countering Hezbollah’s growing influence in the Western Hemisphere?” the aide asked.

He also noted that the United States has a “very robust Israel defense cooperation relationship” and that Hagel’s positions create concerns about how he would handle intelligence sharing and other communication. “There’s definitely a lot that can be chilled, slowed, impacted by a secretary of Defense that is hostile to Israel,” he said.

Hagel has also taken heat from the gay community for objections, in 1998, to an ambassador nominee he characterized as “openly, aggressively gay.”

The criticism has prompted a backlash from many senior members of the foreign policy community in Washington, with a number of foreign policy veterans lobbying to Hagel’s defense, including former Democratic national security advisers Zbigniew Brzezinski and Brent Scowcroft, former Reagan Secretary of Defense Frank C. Carlucci and veteran diplomats, a number of whom served as ambassador to Israel, including Thomas R. Pickering, R. Nicholas Burns, Ryan Crocker, Daniel Kurtzer, William Harrop and Edward Djerejian.

One Hagel backer said he expected opposition to the nomination to dissipate after the Nebraska Republican gets to testify before the Senate and counter what he considers to be a grossly inaccurate portrayal of the retired lawmaker and Vietnam veteran.

The initial critique of Hagel, he said, was an attempt by neoconservatives “to create a spike of concern to kill the nomination.” But, he added, “They failed.”

The Hagel supporter predicted that, as the nominee, Hagel will be able to “solve the LGBT stuff really fast” by coming out and saying “he’s strongly supportive of LGBT rights, LGBT families and service.”

“The world’s evolved, he’s evolved,” he added.

As for the claims that Hagel is not sufficiently pro-Israel, the supporter said there is “too much of a track record where Hagel’s been supportive of Israel.”

“That’ll come out in the hearings,” he said.

Even Hagel backers acknowledge, however, that the confirmation process promises plenty of fireworks. Graham offered a taste of what’s to come on CNN, calling Obama’s pick of Hagel “an in-your-face nomination by the president to all of us who are supportive of Israel.”

Added Graham, “I think it’s an incredibly controversial choice, and it looks like the second term of President Obama is going to be an in-your-face term.”