* Hagel confirmation expected, but vote may be close
* Iran, Iraq, defense budget cuts top concerns of Senate panel
* McCain presses Hagel on past opposition to troop surges (Recasts with comments)
By Phil Stewart and Patricia Zengerle
WASHINGTON, Jan 31 (Reuters) - Republican lawmakers clashed with Chuck Hagel on Thursday at a hearing over his nomination to become the next U.S. defense secretary, attacking his judgment on war strategy and occasionally putting him on the defensive during a heated session.
Critics in Congress have sought to portray Hagel, a former Republican senator and decorated Vietnam War veteran, as soft on Iran and anti-Israel, charges Hagel strongly denied in testimony at the Senate Armed Services Committee hearing.
Republican panel members laid into Hagel, with influential Senator John McCain threatening to vote against him as he questioned Hagel's judgment on the wars in Iraq and Afghanistan, where Hagel opposed surges of American forces.
Even before Hagel started speaking, James Inhofe, the panel's senior Republican, called him "the wrong person to lead the Pentagon at this perilous and consequential time."
"Senator Hagel's record is deeply troubling and out of the mainstream. Too often it seems he is willing to subscribe to a worldwide view that is predicated on appeasing our adversaries while shunning our friends," said Inhofe.
The committee also dwelt on chapters of modern U.S. history that still prompt passionate debate: from the Vietnam War, where Hagel served as an infantryman and was wounded, to President Ronald Reagan's call for nuclear disarmament and the 2003 invasion of Iraq.
Hagel, speaking publicly for the first time since the attacks against his nomination began, at times seemed cautious and halting. He sought to set the record straight, assuring the panel that he backed U.S. policies of preventing Iran from obtaining a nuclear weapon and supporting a strong Israel.
"No one individual vote, no one individual quote, no one individual statement defines me, my beliefs, or my record," Hagel said to the packed hearing room.
"My overall world view has never changed: that America has and must maintain the strongest military in the world."
In an unusual reversal of partisanship, Democrats, more than his fellow Republicans, gave Hagel sympathetic support and time to air his views.
The committee's Democratic chairman, Carl Levin, said his concerns, especially over Hagel's past comments about unilateral sanctions on Iran, had been addressed. "Senator Hagel's reassurance to me ... that he supports the Obama administration's strong stance against Iran is significant," Levin said.
Another member of Obama's second-term national security team, Senator John Kerry, sailed through his nomination hearing before receiving the Senate's overwhelming support on Tuesday.
But Hagel, who publicly broke with his Republican Party over the Iraq War, encountered repeated confrontation. Beyond tough questioning on Israel and Iran, he was also grilled on his view of the Pentagon budget - Hagel is known as an advocate for tighter spending controls.
THE IRAQ SURGE
McCain aggressively questioned Hagel, talking over him at times, and gesturing to express frustration at Hagel's refusal to say plainly whether he was right or wrong in opposing the 2007 surge of American forces in Iraq.
"Your refusal to answer whether you were right or wrong about it is going to have an impact on my judgment as to whether to vote for your confirmation or not," McCain said.
Pressed repeatedly by McCain on the issue, Hagel responded: "I would defer to the judgment of history to sort that out."
It was a far cry from their past, warm ties. McCain campaigned for Hagel in 1996, and Hagel was national co-chairman of the Arizona Republican's unsuccessful 2000 presidential bid.
On Thursday, McCain warned that concerns about Hagel's qualifications ran deep, noting "fundamental disagreements" with members of the committee.
"Our concerns pertain to the quality of your professional judgment and your world view on critical areas of national security, including security in the Middle East," he said.
In the entire Senate, which would vote on Hagel if he is cleared by the committee, only one of the 45 Republicans - Mississippi's Thad Cochran - has said he backs Hagel.
Hagel attempted to soothe concerns and strongly supported current Pentagon positions, detailing his views in 112 pages of written responses to wide-ranging questions submitted by lawmakers ahead of the hearing.
In them, he said that if confirmed as the next defense secretary, he would ensure that the military is prepared to strike Iran if necessary but stressed the need to be "cautious and certain" when contemplating the use of force.
In his opening remarks, Hagel said all options must be on the table to prevent Iran from obtaining a nuclear weapon -language used to suggest the possibility of a nuclear strike.
"My policy is one of prevention, and not one of containment," he said.
Hagel also voiced support for a steady U.S. drawdown in Afghanistan, pledged to ensure equal treatment for women and homosexuals in the military and assured the committee that the United States would maintain an "unshakeable" commitment to Israel's security.
"I will ensure our friend and ally Israel maintains its qualitative military edge in the region," he said.
Most observers expect Hagel will be confirmed by the committee, even if the vote breaks along party lines at 14 Democrats to 12 Republicans.
Democrats control 55 seats in the full Senate and can approve Hagel with no Republican support, but they will need some backing from Hagel's party to overcome procedural hurdles that could stop the nomination. (Additional reporting by David Alexander; Editing by Warren Strobel and Jackie Frank)