WASHINGTON -- The debate over the Iraq War was reignited on Thursday when Sen. John McCain (R-Ariz.) took on Defense Secretary nominee Chuck Hagel for his opposition to the surge of 2007.

McCain and then-Sen. Hagel (R-Neb.) were two of the most prominent voices debating the war at the time, with McCain backing the Bush administration and its neoconservative allies and Hagel part of the growing movement of dissent. And one of McCain's favorite parts of the Bush strategy was the surge, which sent 20,000 additional troops into Iraq.

On Thursday, McCain attempted to re-litigate whether the surge was the right decision, aggressively pressing Hagel on whether he stands by his past statements. He quoted Hagel as saying in 2007 that the surge was the "most dangerous foreign policy blunder in this country since Vietnam."

"Were you right?" McCain asked. "Were you correct in your assessment?"

"Well, I would defer to the judgment of history to sort that out," Hagel said.

"This committee deserves your judgment as to whether you were right or wrong about the surge," McCain responded, adding, "I want to know if you were right or wrong. That's a direct question. I expect a direct answer."

When Hagel continued to insist that the answer was more complicated than a yes or no answer, McCain grew frustrated.

"Will you please answer the question?" McCain said. "Were you correct or incorrect when you said that the surge would be the 'most dangerous foreign policy blunder in this country since Vietnam.' Were you correct or incorrect, yes or no?"

Hagel added that his comment about the "most dangerous foreign policy blunder" was not just about the surge, but about the overall decision to invade Iraq -- a belief he stood by because it took the U.S. focus off Afghanistan.

"Our war in Iraq I think was the most fundamentally bad, dangerous decision since Vietnam," Hagel said.

After Hagel was done speaking, McCain said "any casual observer" knows the surge was the "fundamental factor" in turning around the Iraq War, and was "led by two great leaders, Gen. [David] Petraeus and Amb. [Ryan] Crocker."

In 2008, Obama said he did not believe the surge was necessary to turn around the Iraq War, and his choice of Hagel -- who has made similar comments -- represents one of his clearest breaks with the Bush administration's foreign policy.

Despite Thursday's testy exchange, Hagel and McCain -- both decorated Vietnam veterans -- were once close. In 2000, Hagel was one of the first senators to endorse McCain's presidential bid.

Although Hagel wasn't able to fully express his views on the surge in his exchange with McCain, he did so later in response to a question from Sen. Bill Nelson (D-Fla.), who asked Hagel to elaborate on his Vietnam service.

"I saw the consequences, the suffering and horror of war," said Hagel. "I did question the surge. It wasn't an aberration to me ever. I always ask the question, 'Is this going to be worth the sacrifice?' Because there will be sacrifice."

"In the surge case in Iraq, we lost almost 1,200 dead Americans during that surge, and thousands of wounded," he continued. "Now, was it required? Was it necessary? Sen. McCain has his own opinion on that, shared by others. I'm not sure. I'm not that certain it was required. It doesn't mean I'm right, it doesn't mean I didn't make wrong votes, but that is what guides me when you ask me the question about my time in Vietnam."

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