That intensity was on display last Wednesday as he sat and stewed at a hearing of the Senate Foreign Relations Committee. The panel was considering a resolution condemning President Bush’s proposal to send 21,000 additional troops to Iraq; Hagel, a cosponsor of the resolution, would be the only Republican on the committee to vote for its passage. As he listened to his colleagues make their cases for and against the president’s plan, Hagel told NEWSWEEK he noticed something missing: an acknowledgment that the Senate was talking about committing real troops, the men and women whose “fighting and dying” make a war. He had no prepared text but the words came easily as he took his turn at the mike. Calling Iraq the country’s most divisive issue since Vietnam, he dared his fellow committee members to take a stand. “I think all 100 senators ought to be on the line on this,” he said. “If you wanted a safe job, go sell shoes.” For a moment, his colleagues were silent and stunned. Later that afternoon, Joe Biden, the committee’s Democratic chairman,complimented him on his performance. “I’ve rarely seen such a powerful connection between the heart and the mind,” Biden said. “That was deep in you.”

Viewed from afar, the stuff inside Hagel looks like the stuff that makes Republican presidential candidates. He is a third-generation party member who grew up idolizing Teddy Roosevelt and Dwight Eisenhower. He says he was the only student in his Roman Catholic high school to support Richard Nixon over John F. Kennedy in the 1960 presidential election–and when he cast his first vote, an absentee ballot from Vietnam, it was for Nixon’s winning ticket in 1968. His conservative credentials are impeccable: according to Congressional Quarterly, he voted with the White House more times in 2006 than any other senator. He is manly, Middle American–and when he talks about military matters, he exudes the cool confidence of a warrior-statesman who knows that war is hell.

But Hagel, who as of late last week was in the final stages of weighing a presidential run, is never mentioned in the top tier of Republican candidates for one, simple reason: since the initial buildup to the war in Iraq, he has assailed the Bush administration’s policy–in sharp words, in constant refrain and, most unforgivably, in public. His outburst last week was the culmination of a four-year campaign to raise public outrage about a war he’s always considered disastrous. His stance has earned him the enmity of the White House. Asked about Hagel last week in an interview with NEWSWEEK, Vice President Dick Che-ney said: “I believe firmly in Ronald Reagan’s 11th Commandment: thou shalt not speak ill of a fellow republican. But it’s very hard sometimes to adhere to that where Chuck Hagel is involved.”

Cheney, however, doesn’t necessarily speak for his party. In the latest NEWSWEEK Poll, only 30 percent of voters approve of Bush’s performance as president. Even 31 percent of Republicans think Congress has not done enough to challenge the administration on the war. After the disastrous 2006 midterm elections, Republicans are no longer taking their talking points on Iraq from the White House–several members of Hagel’s caucus have suggested they’d support a resolution criticizing the surge when it comes before the Senate this week. Meanwhile, the three leading contenders for the Republican nomination, John McCain, Mitt Romney and Rudy Giuliani, are all vulnerable on the war–all three are in the minority of Americans who support the president’s plan. Hagel may be the one Republican who can fully separate the party from the troubled legacy of George W. Bush as the GOP looks to 2008.

The tale of Hagel’s reluctant rebellion is the story of a man haunted by wars then and now–and of a party at a crossroads, weighing Hagel’s past transgressions of disloyalty against the simple necessities of survival. Chuck Hagel has a lifetime of lessons in loyalty and war. His father, Charlie, flew raids for the Army Air Corps over the islands of the South Pacific during World War II. Born in 1946, Chuck was the eldest of four boys and grew up fascinated by the great conflict his father had fought in. In his childhood, his family moved through a series of Midwestern towns, but his father would always serve as commander of the local VFW. His mother and father taught their boys that loyalty to country was paramount and that every generation had its war. “It was as religious as going to church,” Hagel tells NEWSWEEK.

Charlie Hagel never talked much about his war. A member of the fabled Greatest Generation, he thought it unseemly to brag about his exploits on the battlefield. But there was something darker enforcing the silence, memories that gave him nightmares and caused him to drink too much. “If they’d had the resources available back then,” says Hagel’s brother Tom, “he would have been diagnosed with posttraumatic stress disorder. I don’t know what happened to him over there.” Charlie never got a chance to tell his sons; he died of a heart attack when Chuck was just 16. For decades, all his boys would really know of his time at war was what they could find in a musty attic, the things Charlie had carried back: a handmade machete, a grass hula skirt, black-and-white photos of Japanese Zero fighters hurtling across the Pacific sky.

Two Hagel brothers would soon learn the lessons of the battlefield firsthand. Chuck and Tom were both sent to Vietnam where by some oversight (neither brother can explain it) they managed to defy Army regulations and fight in the same unit. In time, each brother would get a chance to save the other’s life. In rare moments of reflection, the brothers spoke of their father, wondering how their experiences matched up with his. “Southeast Pacific. Jungles. Fighting the Asians,” Chuck says. “We often talked about that.” Mostly, though, the brothers focused on fighting–and staying alive. It was 1968, America’s bloodiest year in the war, and on the ground the brothers were hardened by a grisly conflict they tried not to think of as futile. “You see it today in Iraq,” says Tom. “We go in, kill all these insurgents, lose all those people. Then we leave town and they just move back in. Same damn thing we did every day over there.”

Their tours up, the Hagel boys returned home, Vietnam still swirling in their heads. Tom quickly turned against the war, convinced he had toiled gruesomely for a mistake. Chuck, stubbornly patriotic, couldn’t abide this talk; he and Tom quarreled constantly, sometimes coming to blows. But Hagel harbored his own silent doubts. He spent the ’70s devouring histories of American involvement in Southeast Asia, eventually (and privately) concluding that Congress’s failure to ask tough questions about the conflict in Vietnam amounted to gross negligence. He recalls making a vow to himself: “If America were to go to war again and I was in a position to influence things, I would do everything I could to understand the reality and not allow another Vietnam to occur.”

Hagel got his chance to extend some influence when he won election to the Senate in 1996. He was an enthusiastic partisan, leading his state’s Republican Party as Nebraska shifted solidly red. But Hagel’s party loyalties extend only so far. From the early days of the Bush administration, he was uneasy with the president’s apparent zest for war in Iraq and worried that a post-Saddam Iraq could not be stabilized without a broad international coalition. He shared his discomfort in frank, private conversations with administration officials and, as his detractors noted, on more than one Sunday talk show. Hagel makes no apology for his public candor. “The reason we have a very, very thin layer of confidence in leadership by the American public is because we don’t answer their questions and we don’t play straight,” he says. “So when Senator Hagel gets asked the question on a talk show on Sunday morning, ‘What do you really think about what we’re doing?’ I’ve never pulled my punches.” In August 2002, Cheney traveled to the Veterans of Foreign Wars Conference and declared that “Saddam Hussein now has weapons of mass destruction.” Shocked, Hagel called up his closest allies in the Bush administration, Secretary of State Colin Powell and his deputy Richard Armitage. “That was a war speech,” Hagel told them. His friends assured him that Cheney had gone too far and that war could still be diverted through diplomacy.

Hagel still worried and the war came. When the Senate debated a resolution authorizing the administration to use force to remove Saddam, Hagel took to the Senate floor and spoke in damning, eloquent terms of the folly of the whole affair. He then proceeded to grant the president the authority he needed. It was a painful contortion–one that could hurt him in a presidential contest–perhaps understood only by those who knew Hagel best. “I’m sure in the end it was, ‘Damn, he’s my president’,” Tom says of his brother’s vote. “It was, ‘I have strong doubts about things, but I can’t be disloyal’.” Hagel, who now says he regrets his vote, admits a sense of duty played a role. “He’s the commander in chief,” Hagel says. “We all owe some loyalty, not to the president, but to the office itself.”

To many Republicans, Hagel’s gesture of obedience wasn’t enough. As Iraq quickly deteriorated after Saddam’s ouster, Hagel loudly voiced his frustration with the Bush administration–first urging the president to send in more troops, then saying he had no confidence in Secretary of Defense Donald Rumsfeld and, in time, concluding there was no purely military solution for Iraq. Conservative bloggers began calling him chief of the Even Republicans–wobblers whose names filled press stories on how “even Republicans” criticized the president, who was still reasonably popular. Reaction was particularly harsh from constituents back home. “It was, ‘Senator, you’re not as smart as the president’,” says Hagel. " ‘You’re just a Vietnam-vet crybaby’."

In the midst of the maelstrom, Hagel found an unexpected voice of consolation: his father’s. In the fall of 2005, the Hagel brothers received a box from some cousins–it contained letters Charlie had written home during and after World War II. In many ways, the letters provided a tragic portrait of the young airman, coping with the strains of battle by imagining an idyllic postwar world. “That’s what they all wanted,” Hagel says. “They wanted peace, they wanted stability, and they didn’t want any more of what they saw.” But in one letter Hagel shared with The Washington Post in 2005, Charlie makes his own reality plain. “If I thought I would ever have a son who would have to go through this,” he wrote to his sister Doris in 1944, “I would never get married.”

Hagel’s own two children, daughter Allyn, 16, and son Ziller, 14, are still too young to worry about war, but they are on his mind. As he nears his decision on running for president–a decision he says will come sometime in “the next couple weeks”–it is the effect on his family, he says, that weighs most heavily. This is, of course, what all politicians say while figuring out if they’ve actually got a shot. Hagel may have a hard time making his own case. With McCain and Romney running hard, the supply of Republican campaign talent, and cash, dwindles by the minute. For Hagel to succeed in the primaries, he’d have to count on a Republican Party acting decidedly unlike itself–turning to a fresh face and ignoring past indiscretions. “It’s a question of taste,” says an adviser to one Republican candidate who would not publicly criticize Hagel. “You don’t have to love the war to think it’s inappropriate when a United States senator constantly berates the president in public.”

But Hagel, along with Democratic candidates Barack Obama and John Edwards, is that rare 2008 contender whose position on the war is a potential strength, not a weakness, in a general election campaign. In fact, Tom Cole, the new chairman of the National Republican Campaign Committee, says that while he disagrees with Hagel’s war stance, he’s urging 2008 congressional candidates to show a similar candor when talking about the war. “I think we’ve reached that point in the debate,” Cole says. “He’s being intellectually honest.”

Hagel’s speech at the Foreign Relations Committee last week earned him new fans on the left, some of whom are hoping he’ll run for the White House as an independent–a notion he dismisses as ludicrous. He chafes when it’s suggested he could run as an “antiwar candidate,” and thinks he’s earned the right to define himself. “I’ve always said you’d better listen to the guys who’ve had the experience of having to actually carry the rifle,” he says, “and see the tragedy of war … Down in the mud, having to face the fact his buddy’s brains are next to him because his head’s been shot off.” Hagel speaks these words with sadness. He walks the halls of the Senate with a gray melancholy that makes some who know him wonder if he has the fight in him for a long-shot presidential run. But Hagel is an old soldier who has fought without question before. The wound on his face was born in a flash of fire.