(NBC News) -- Former senator Chuck Hagel, President Barack Obama's choice to be secretary of defense faced testy and skeptical questions from Republicans during his confirmation hearing before the Senate Armed Services Committee Thursday.
At one point the Iraq war and President George W. Bush's 2007 surge of U.S. troops into Iraq became the heated focus of the hearing.
Sen. John McCain, R- Ariz., repeatedly pressed Hagel, a fellow Vietnam War veteran, on whether he had been right or wrong to say that the 2007 surge was "the most dangerous foreign policy blunder since Vietnam."
When McCain angrily said "Will you please answer the question?"
Hagel told McCain "I'm not going to give you a yes or no answer…. I'll defer that judgment to history."
When McCain shot back that Hagel had been wrong about the surge, Hagel said his "most dangerous blunder" comment had been "not just about the 2007 surge but the overall war of choice going into Iraq" in 2003.
As a senator, Hagel voted for the resolution authorizing Bush to invade of Iraq, but later turned critical of Bush's conduct of the operation. At one point in 2007 he suggested that Bush might face impeachment.
At the end of their tense confrontation over the Iraq war, McCain told Hagel, "History has already made a judgment about the surge, sir, and you're on the wrong side of it."
Despite what will be an entire day of adversarial interrogation, it seems nearly certain that the Senate will vote to confirm Hagel.
The ranking Republican on the Armed Services Committee, Sen. Jim Inhofe of Oklahoma, pressed Hagel on his support for endorsement of Global Zero, the movement calling for abolition of nuclear weapons by 2030. Hagel served on the Global Zero U.S. Nuclear Policy Commission which issued a report last May calling for an 80 percent reduction in the U.S. nuclear arsenal.
Hagel told Inhofe that his own position "has never been unilateral disarmament."
But last May's Global Zero report say that a drastically smaller U.S. arsenal could be negotiated bilaterally with Russia "or implemented unilaterally."
In his opening statement Hagel pledged that he would maintain "a modern, strong, safe, ready, and effective nuclear arsenal. America's nuclear deterrent over the last 65 years has played a central role in ensuring global security and the avoidance of a World War III. I am committed to modernizing our nuclear arsenal."
But Inhofe accused Hagel of "a recent trend of policy reversals that seem based on political expediency rather than on core beliefs" and accused him of a willingness to "walk back or alter his positions" in an attempt to win Senate confirmation.
He said Hagel's record "is deeply troubling and out of the mainstream. Too often, it seems, he's willing to subscribe to a world-wide view that's predicated on appeasing our adversaries while shunning our friends."
Inhofe cited Hagel's' refusal to sign a Senate letter to President Bill Clinton in 2000 affirming U.S. solidarity with Israel. "Sen. Hagel was one of just four who refused to sign that letter," Inhofe said.
Inhofe also assailed Hagel for advocating direct negotiations with the regime in Tehran.
The Oklahoma Republican has announced he'll oppose Hagel, but has implied that he expects the former Nebraska senator will win confirmation.
Hagel, who was seriously wounded while serving as an Army infantryman in Vietnam, was a Republican senator from Nebraska from 1997 to 2009 but did not support Republican presidential candidates McCain in 2008 or Mitt Romney last year.
Hagel told the panel in his opening remarks that is "fully committed to the President's goal of preventing Iran from obtaining a nuclear weapon, and -- as I've said in the past -- all options must be on the table to achieve that goal. My policy is one of prevention, and not one of containment and the President has made clear that is the policy of our government."
He also pledged said he would "ensure our friend and ally Israel maintains its Qualitative Military Edge in the region and will continue to support systems like Iron Dome, which is today saving Israeli lives from terrorist rocket attacks."
In his opening statement, Armed Services Committee chairman Sen. Carl Levin, D- Mich., said one past statement by Hagel "which has raised concern" is his recommendation that the United States conduct "direct, unconditional and comprehensive talks with the Government of Iran."
Levin said, "The formulation used by Sen. Hagel seemed to imply a willingness to talk to Iran on some issues that I believe most of us would view as non-negotiable, and therefore any willingness to talk to Iran would need to be highly conditional."
But Levin said Hagel had given him assurances that he'd support what Levin called "the Obama Administration's strong stance against Iran."
Hagel began his testimony with a call for a defense policy that transcends party differences, telling the committee, "We cannot allow the work of confronting the great threats we face today to be held hostage to partisanship on either side of the aisle" or by differences between the executive branch and the Congress.
Hagel promised the committee members Thursday that he would work with them and seek their views.
"I know Secretary Panetta has put a strong emphasis on reaching out to the Congress," he said. "I, like Leon, come from the Congress, and respect and understand this institution's indispensable role in setting policy and helping govern our country."
Alluding to some of his provocative statements in the past, Hagel said in his opening remarks Thursday, "No one individual vote, no one individual quote, no one individual statement defines me, my beliefs, or my record. My overall worldview has never changed: that America has and must maintain the strongest military in the world; that we must lead the international community to confront threats and challenges together…."