(AP) -- Hillary Rodham Clinton strove to close the book on the worst episode of her tenure as secretary of state Thursday, battling hours of Republican questions in a hearing that grew contentious but revealed little new about the 2012 attacks in Benghazi, Libya. She firmly defended her record while seeking to avoid any mishap that might damage her presidential campaign.

Pressed about events before and after the deaths of four Americans, Clinton had confrontational exchanges with several GOP lawmakers but also fielded supportive queries from Democrats. The most combative moments focused on accusations about the Obama administration's shifting early public accounts of the attacks.

However, five hours into the hearing, Republicans had yet to ask the Democratic presidential front-runner a single question about the night of Sept. 11, 2012, itself.

The committee's chairman, Trey Gowdy, portrayed the panel as focused on the facts after comments by fellow Republicans describing it as an effort designed to hurt Clinton's presidential bid. Democrats have pounced on those earlier remarks and have pointed out that the probe has now cost U.S. taxpayers more than $4.5 million and, after 17 months, has lasted longer than the 1970s Watergate investigation.

Gowdy, a former federal prosecutor, said the Republicans' efforts were not a prosecution.

Contradicting him, Rep. Adam Smith, a Democrat from Washington, told Clinton: "The purpose of this committee is to prosecute you."

In one tense moment, Republican Rep. Jim Jordan of Ohio accused Clinton of deliberately misleading the public by linking the Benghazi violence at first to an Internet video insulting the Muslim Prophet Muhammad.

Clinton, stone-faced for much of the hearing, smiled in bemusement as Jordan cut her off from answering. Eventually given the chance to comment, she said only that "some" people had wanted to use the video to justify the attack that killed Ambassador Chris Steven and three other Americans, and that she rejected that justification.

The argument went to the origins of the disagreement over Benghazi and how President Barack Obama and his top aides represented the attack in the final weeks of his re-election campaign. And it reflected some of the raw emotion the deadly violence continues to provoke, something Clinton will have to face over the next year of her White House bid even if the Republican-led special investigation loses steam.

For Clinton, the political theater offered opportunity and potential pitfalls. It gave her a high-profile platform to show her self-control and command of foreign policy. But it also left her vulnerable to claims that she helped politicize the Benghazi tragedy.

"There were probably a number of different motivations" for the attack, Clinton said, describing a time when competing strands of intelligence were being received and no clear picture had yet emerged. Speaking directly to Jordan, she said: "The insinuations that you are making do a great disservice" to the diplomats and others involved.

"I'm sorry that it doesn't fit your narrative. I can only tell you what the facts were," Clinton said.

There were no gaffes for Clinton and -- beyond that exchange-- few heated interactions. She never raised her voice as she had at a Senate hearing on Benghazi in January 2013, when she shouted: "What difference, at this point, does it make?" Given that Republicans campaigned off that oft-repeated sound bite, the lack of an indelible image from Thursday's hearing will have suited Clinton's campaign fine.

Instead, it was the panel's members who engaged among themselves in the nastiest fight, with Clinton merely observing. Democrats pressed for the release of the full transcript of a Clinton adviser's private testimony, drawing the Republican chairman, Trey Gowdy of South Carolina, into an angry debate. The panel eventually voted against the release, all five Democrats in favor, all seven Republicans against.

Thursday's appearance came at a moment of political strength for Clinton. A day earlier, a potential rival for the Democratic nomination, Vice President Joe Biden, announced he would not join the race. Clinton also is riding the momentum of a solid debate performance last week.

Gowdy, a former federal prosecutor, said important questions remain unanswered: Why was the U.S. in Libya, why were security requests denied, why was the military not ready to respond quickly on the 11th anniversary of 9/11 and why did the Obama administration change its story about the nature of the attacks in the weeks afterward?

"These questions linger because previous investigations were not thorough," Gowdy said.

Clinton, in turn, focused on the bigger picture, starting with a plea for the U.S. to maintain its global leadership role despite the threat posed to its diplomats. She said Benghazi already had been exhaustively scrutinized and that perfect security can never be achieved, drawing on the various attacks on U.S. diplomatic and military installations overseas during the presidencies of her husband, Bill Clinton, in the 1990s and Ronald Reagan a decade earlier.

"In Beirut we lost far more Americans, not once but twice within a year," she said of the 1983 attacks in Lebanon that killed more than 250 Americans and dozens of others. "People rose above politics. A Democratic Congress worked with a Republican administration to say, 'What do we need to learn?'"

Wearing a dark suit, Clinton appeared somber before the panel, holding her chin in her hand while Gowdy interrogated her. She nodded occasionally, such as when the committee's top Democrat, Rep. Elijah Cummings of Maryland, described the entire probe as a partisan campaign replete with implausible conspiracy theories.

The Republican criticism has included contentions by some lawmakers including that Clinton personally denied security requests and ordered the U.S. military to "stand down" during the attacks. None of these were substantiated in the independent Accountability Review Board investigation ordered by Clinton after the attacks or by seven subsequent congressional investigations.

Some questions Thursday dealt indirectly with Clinton's use of a private email account and server while serving as Obama's chief diplomat, another issue that has beset her campaign.

While she testified, FBI Director James Comey was speaking to lawmakers elsewhere on Capitol Hill, a reminder that Clinton may face more examinations on the matter in the months ahead. The FBI has said little thus far about its investigation of the private email server.

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