Defense Secretary Leon Panetta came to the aid of former Sen. Chuck Hagel, the man President Barack Obama nominated to succeed him, saying on NBC’s Meet the Press, “The political knives were out for Chuck Hagel” during his confirmation hearing last week.

In nearly eight hours of testimony before the Senate Armed Service Committee on Thursday, Hagel spent much time revising and clarifying his previous remarks – including a spontaneous error at the hearing itself on whether United States policy toward Iran’s nuclear weapons program was one of containment.

Panetta complained that the members of the committee spent too little time questioning Hagel about the current challenges the Defense Department faces, such as looming budget cuts, and spent too much time examining statements Hagel made in the past.

Panetta insisted to NBC’s Chuck Todd that Hagel was “absolutely” prepared to take his place leading the Defense Department.

Panetta’s backing of Hagel was seconded by the chairman of the Joint Chiefs of Staff, Gen Martin Dempsey, who said “in helping prepare him for his confirmation hearings, we had several opportunities to talk about strategy. And I found him well-prepared and very thoughtful about it.”

As the Armed Services Committee prepares to hold a hearing Thursday on last September’s attack on the U.S. diplomatic mission in Benghazi, Panetta said he looked forward “to presenting what we know about what took place.” Congressional Republicans have questioned why there were no U.S. military aircraft or other forces in proximity to Benghazi that could have been dispatched to help defend Ambassador Chris Stevens and other US personnel. Stevens and three others were killed in the attack.

Addressing the Defense Department’s airlift and intelligence-sharing role in assisting the ongoing French military intervention in the North African nation of Mali, Panetta said, “We are now working with France to make sure that al Qaida has no place to hide, even in North Africa.”

Dempsey added that in North Africa “the regimes that you used to maintain control over that space that would, in fact, be part of the solution of keeping al Qaida and its affiliates at bay are no longer there.”

The popular uprisings of the 2011 Arab Spring, Dempsey said, “stripped that away” leaving “ungoverned space” or “a period at which geography is less governed than it used to be.” That lack of control has allowed jihadist groups such as al Qaida in the Islamic Maghreb (AQIM) to flourish.

Turning to Iran and its nuclear program, Panetta said, “The intelligence we have is they have not made the decision to proceed with the development of a nuclear weapon. The regime in Tehran is enriching uranium.  They continue to do that.”

He added, “I can't tell you they are, in fact, pursuing a weapon, because that's not what intelligence says they're doing right now. But every indication is they want to continue to increase their nuclear capability. And that's a concern. And that's what we're asking them to stop doing.”

Vice President Joe Biden said Saturday that the Obama administration is “would be prepared to meet bilaterally with the Iranian leadership,” but that talks would need to be serious, have an agreed-upon agenda, and not be merely an exercise.

On the threat of spending cuts, known in Capitol language as “sequester,” scheduled to start on March 1 that are mandated by the Budget Control Act, Panetta said, “If Congress stands back and allows sequester to take place, I think it would really be a shameful and irresponsible act.”

He added that the spending cuts this year – amounting to about 12 percent of Pentagon outlays apart from overseas operations – would “badly damage the readiness of the United States of America.”

Panetta, who served as head of the Office of Management and Budget under President Clinton and as chairman of the House Budget Committee in the late 1980s, said, “As somebody who's worked with budgets throughout my life, in order to deal with the deficit problem, you've got to deal with entitlements. You have to deal with revenues. And you have to deal with discretionary (spending).”

Although Republicans such as Sen. John McCain of Arizona have accused Obama of failing to take the lead in finding a way to avoid the cuts required by the Budget Control Act, Panetta said, “I think he's pushing as hard as he can…. The president of the United States has indicated the concern about sequester. He's indicated his concern about maintaining a strong national defense.  And he's proposed a solution to this. The ball is in Congress's court. They have got to take action to delay sequester.”

Updated at 5:53 p.m. ET – Former Sen. Chuck Hagel, President Barack Obama’s choice to be secretary of defense, finished a day-long marathon confirmation hearing before the Senate Armed Services Committee Thursday, enduring nearly eight hours of testy and skeptical questions from Republicans.

At the start of Thursday’s hearing, it seemed nearly certain that the Senate would vote to confirm Hagel. But the nominee labored at certain points during the day to clarify and explain his comments. Whether his occasional stumbles were serious enough to jeopardize his confirmation was not clear by the end of the testimony.

There are 55 senators in the Democratic caucus and 45 Senate Republicans, so if there’s no filibuster, Hagel would seem assured of confirmation. The last time the Senate rejected a Cabinet nominee was in 1989 when there was a Republican president and a Democratic-controlled Senate. 

Republican senators confronted Hagel with quotations from statements he had made months or years ago – and sometimes he apologized for them or amended them.

Late in the day Sen. Mike Lee, R- Utah, asked Hagel whether he’d said in 2003 that Israel keeps Palestinians “caged up like animals” and whether he still believes that.

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“Like many things I’ve said, I would like to go back and change the words and the meaning,” Hagel told Lee. “If I had a chance to go back and edit it, I would. I regret that I used those words.”

But he said he’d made his statement “in a larger context … (addressing) the frustration in what’s happening (in Israel) which is not in Israel’s interest” and mentioned the need “to find ways that we can help bring peace and security to Israel.”

Quizzed by both Sen. Kirsten Gillibrand, D-N.Y., and Sen. David Vitter, R- La., on a statement he’d made calling the Iranian government a “legitimate” one, Hagel said, “I should have said ‘recognized’ instead of ‘legitimate.’”

At one point he told Sen. Saxby Chambliss, R- Ga., regarding U.S. policy toward Iran’s efforts to build nuclear weapons: “I’ve just been handed a note that I misspoke and said I supported the president’s position on ‘containment.’ If I said that, I meant to say that obviously – his position on containment – we don’t have a position on containment.”

Hagel then said, “I’ve had more attention paid to my words in the last eight weeks than I ever thought possible.”

This prompted Armed Services Committee chairman Sen. Carl Levin, D- Mich., to intervene, “Just to make sure your correction is clear, we do have a position on containment – which is we do not favor containment.” Hagel quickly concurred with Levin’s statement.

Hagel told the panel in his opening remarks that he is “fully committed to the president's goal of preventing Iran from obtaining a nuclear weapon,” and that “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.”

At another point, Hagel, explaining his criticism quoted in a 2008 book by Aaron David Miller, of “the Jewish lobby” and his allegation that “it intimidates a lot of people” in Congress – comments for which Hagel has apologized – said he ought to not have used the word “intimidates.”

“I should have used ‘influence,’” he said.

Later, Sen. Lindsey Graham, R- S.C., challenged Hagel to “name one dumb thing we’ve been goaded into doing” by the pro-Israel lobby or to identify one member of Congress whom the pro-Israel lobby had intimidated. Hagel said, “I didn't have in mind a single person," and did not identify any policy the U.S. government had been goaded into.

Sen. Ted Cruz, R-Texas, played Hagel a recording of an interview Hagel did in 2009 with an al Jazeera program. A listener submitted a question asking about “the image of the United States is that of the world’s bully” and whether the United States needed “to change the perception and the reality” before asking other nations to reduce their arsenals. In that 2009 program Hagel began his reply by saying, “Her observation is a good one … .”

When Cruz asked Hagel to explain this reply, he said Thursday, “I think my comment was it was a relevant and good observation. I don’t think I said that I agree with it.”

Early in the testimony, 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 congressional resolution authorizing Bush to invade Iraq, but later turned critical of Bush’s conduct of the operation.

Other Republicans on the committee repeatedly 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 ranking Republican committee member Sen. Jim Inhofe of Oklahoma that his position “has never been unilateral disarmament.”

Kevin Lamarque / Reuters

Former Senator Chuck Hagel, R-Neb., testifies during a Senate Armed Services Committee hearing on his nomination to be Defense Secretary, on Capitol Hill, Jan. 31, 2013.

And he said the Global Zero report was discussing “illustrative possibilities” and “scenarios” and wasn’t urging specific policies.

But last May’s Global Zero report, which Hagel signed on to, says 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 an 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,” he said.

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.

Americans for a Strong Defense, a Republican-leaning group that opposes former GOP Sen. Chuck Hagel's nomination to be defense secretary, is airing new TV ads hitting Hagel in four states where Democratic senators are up for re-election in 2014.

The four states: Alaska (where Sen. Mark Begich is up for re-election next year), Arkansas (Sen. Mark Pryor), Colorado (Sen. Mark Udall), and Louisiana (Sen. Mary Landrieu).

"Barack Obama’s nominee for secretary of defense wants America to back down," one of these ads goes. "An end to our nuclear program. Devastating defense cuts. A weaker country. Call Mark Begich and tell him to say no to Chuck Hagel –- before it’s too late."

A spokesman for Americans for a Strong Defense says the ad buy is "significant," and the advertisements will air on broadcast and cable in these four states.

Sen. Chuck Schumer (D-NY), who is seen as a key to Chuck Hagel's becoming Defense secretary, is throwing his support behind the former Nebraska Republican senator -- despite past controversial statements on Israel, Iran, and the "Jewish lobby."

"Based on several key assurances provided by Senator Hagel, I am currently prepared to vote for his confirmation," Schumer said in a statement. "I encourage my Senate colleagues who have shared my previous concerns to also support him."

Spencer Platt / Getty Images

Sen. Charles Schumer (D-NY) speaks during a news conference where it was announced that free Wi-Fi will be provided by Google to the Manhattan neighborhood of Chelsea on January 8, 2013 in New York City.

He added, "I know some will question whether Senator Hagel's assurances are merely attempts to quiet critics as he seeks confirmation to this critical post. But I don't think so. Senator Hagel realizes the situation in the Middle East has changed, with Israel in a dramatically more endangered position than it was even five years ago. His views are genuine, and reflect this new reality. ... In general, I believe any President deserves latitude in selecting his own advisors. While the Senate confirmation process must be allowed to run its course, it is my hope that Senator Hagel's thorough explanations will remove any lingering controversy regarding his nomination."

With Schumer's support, Hagel is seen as a likely shoo-in to win confirmation.

Full statement from Schumer's office:

U.S. Senator Charles E. Schumer released the following statement Tuesday regarding the nomination of former Senator Chuck Hagel’s nomination for Secretary of Defense:

When Senator Hagel’s name first surfaced as a potential nominee for Secretary of Defense, I had genuine concerns over certain aspects of his record on Israel and Iran. Once the President made his choice, however, I agreed to keep these reservations private until I had the opportunity to discuss them fully with Senator Hagel in person.

In a meeting Monday, Senator Hagel spent approximately 90 minutes addressing my concerns one by one. It was a very constructive session. Senator Hagel could not have been more forthcoming and sincere.

Based on several key assurances provided by Senator Hagel, I am currently prepared to vote for his confirmation. I encourage my Senate colleagues who have shared my previous concerns to also support him.

In our meeting Monday, Senator Hagel clarified a number of his past statements and positions and elaborated on several others.

On Iran, Senator Hagel rejected a strategy of containment and expressed the need to keep all options on the table in confronting that country. But he didn’t stop there. In our conversation, Senator Hagel made a crystal-clear promise that he would do “whatever it takes” to stop Tehran from obtaining nuclear weapons, including the use of military force. He said his “top priority” as Secretary of Defense would be the planning of military contingencies related to Iran. He added that he has already received a briefing from the Pentagon on this topic.

In terms of sanctions, past statements by Senator Hagel sowed concerns that he considered unilateral sanctions against Iran to be ineffective. In our meeting, however, Senator Hagel clarified that he ‘completely’ supports President Obama’s current sanctions against Iran. He added that further unilateral sanctions against Iran could be effective and necessary.

On Hezbollah, Senator Hagel stressed that—notwithstanding any letters he refused to sign in the past—he has always considered the group to be a terrorist organization.

On Hamas, I asked Senator Hagel about a letter he signed in March 2009 urging President Obama to open direct talks with that group’s leaders.

In response, Senator Hagel assured me that he today believes there should be no negotiations with Hamas, Hezbollah or any other terrorist group until they renounce violence and recognize Israel’s right to exist.

Senator Hagel volunteered that he has always supported Israel’s right to retaliate militarily in the face of terrorist attacks by Hezbollah or Hamas. He understood the predicament Israel is in when terrorist groups hide rocket launchers among civilian populations and stage attacks from there. He supported Israel’s right to defend herself even in those difficult circumstances.

In keeping with our promises to help equip Israel, Senator Hagel pledged to work towards the on-time delivery of the F-35 joint strike fighters to Israel, continue the cooperation between Israel and the U.S. on Iron Dome, and recommend to the President that we refuse to join in any NATO exercises if Turkey should continue to insist on excluding Israel from them.  Senator Hagel believes Israel must maintain its Qualitative Military Edge.

Regarding his unfortunate use of the term “Jewish lobby” to refer to certain pro-Israel groups, Senator Hagel understands the sensitivity around such a loaded term and regrets saying it.

I know some will question whether Senator Hagel’s assurances are merely attempts to quiet critics as he seeks confirmation to this critical post. But I don’t think so. Senator Hagel realizes the situation in the Middle East has changed, with Israel in a dramatically more endangered position than it was even five years ago. His views are genuine, and reflect this new reality.

On issues related to female and LGBT service members, Senator Hagel provided key assurances as well. He said he is committed to implementing the Shaheen amendment to improve the reproductive health of military women. He also supports the full repeal of Don’t Ask, Don’t Tell.

In general, I believe any President deserves latitude in selecting his own advisors. While the Senate confirmation process must be allowed to run its course, it is my hope that Senator Hagel’s thorough explanations will remove any lingering controversy regarding his nomination.

Chuck Hagel, a former Republican senator and rumored top pick for the next Secretary of Defense, has apologized for his 1998 opposition to a ambassadorial nominee because he was "openly, aggressively gay."

"My comments 14 years ago in 1998 were insensitive," Hagel said in a statement. "They do not reflect my views or the totality of my public record, and I apologize to Ambassador Hormel and any LGBT Americans who may question my commitment to their civil rights.  I am fully supportive of ‘open service’ and committed to LGBT military families.”

Hagel's original comment came in response to the nomination of James Hormel, tapped by Bill Clinton to be ambassador to Luxembourg. At the time, Hagel questioned how an openly gay ambassador would be effective at "representing our lifestyle, our values, our standards."

LGBT groups have critiqued Hagel for the 1998 statement, as well as for his long-time support for now-repealed "Don't Ask, Don't Tell" policy towards gay military servicemembers.

The Human Rights Campaign, an LGBT rights organization, praised Hagel's apology in a statement.

"Senator Hagel's apology and his statement of support for LGBT equality is appreciated and shows just how far as a country we have come when a conservative former Senator from Nebraska can have a change of heart on LGBT issues," said HRC President Chad Griffin. "Our community continues to add allies to our ranks and we're proud that Senator Hagel is one of them."

Former Republican Sen. Chuck Hagel is likely to be President Barack Obama's next pick for Secretary of Defense, although the White House has yet to finalize its decision for the cabinet appointment. 

A former Pentagon official tells NBC News that Hagel is the likely pick for the post, while another White House insider says that, while Hagel is a top candidate, it's unclear if the president has made a final decision. 

A senior administration official tells NBC News that "no decision" has been made on the nomination. 

Bloomberg News reported Thursday that President Barack Obama spoke to Hagel about the position on December 4. 

Hagel, who served two terms in the United States Senate representing his home state of Nebraska, has been a member of the president's Foreign Intelligence Advisory Board as well as a member of the faculty of Georgetown University since leaving Capitol Hill in 2009. 

He also accompanied then-Senator Obama on his campaign trip to Afghanistan, Iraq and the Middle East in the summer of 2008. 

While in the Senate, he was a member of four Senate committees, including the Committee on Foreign Relations and the Select Committee on Intelligence. 

NBC's Carrie Dann contributed to this report.