On November 2nd, Americans will vote in the first wartime election since Vietnam. Like that earlier war, the war in Iraq has exposed deep divisions in how Americans see this country and its place in the world. It has also exposed major differences between the two candidates, George W. Bush and John F. Kerry.

"Americans are choosing their next commander in chief. And the two candidates have squared off over the Iraq war," says producer Martin Smith. "These two men couldn't be more different. Bush leads from the gut, Kerry from the head. Bush is drawn to certainty, Kerry embraces complexity. Bush is ambitious, Kerry is more cautious and conservative."

Culled from more than fifty interviews with the candidates' families, friends, colleagues, and political adversaries, "The Choice 2004" takes a hard look at the character, experience, and worldviews of Bush and Kerry and illuminates defining moments of their lives with rare archival footage. The program also examines both candidates' decision-making on going to war in Iraq.

"If you want to know who George Bush is, look at the Iraq war," journalist Bob Woodward tells FRONTLINE. "I asked him, `Do you have any doubt?' And I asked it in the starkest terms. Because Tony Blair had said when he gets hate mail saying `My son died in your war, and I hate you,' Blair said publicly, `You can't get letters like that and not have doubt.' I read that to President Bush in the Oval Office, thinking he might even say, `Well, you know, Blair's got a point.' He just ignited and just said, `No doubt. I have no doubt.'"

Kerry's response to the war in Iraq has been more nuanced, and he has spent a great deal of time on the campaign trail justifying why he voted for the president's Iraq resolution and now opposes the war.

"Today, what's prized, what all of us sportscasters who cover political campaigns want, is a message. You know, give me the ten-second sound bite over and over. Don't deviate," says Kerry's former chief counsel, Jack Blum. "John Kerry knows enough to know that the world is not a sound bite world. He is always tempted to give you the nuances that he knows. And to tell you that the problem is much more complicated than you think it is. And to worry about that complexity. And maybe that is his biggest single weakness as a candidate."

It was during America's war in Vietnam that the first differences between George W. Bush and John F. Kerry began to emerge. Dan Barbiero, Kerry's roommate at Yale, tells FRONTLINE why Kerry signed up for Vietnam despite his opposition to the war. "We grew up believing that our obligation was to serve our country when called on. I mean that really was a lot of it. It sounds really corny. But that's what we believed."

Two years later, George W. Bush needed to decide what he would do. His Yale classmate Roland Betts tells FRONTLINE, "By the time 1968 rolled around, everybody in the class of '68 was trying to figure out (a) how they felt about Vietnam, and (b) what they were going to do about it. Is this something that you wanted to be a part of? Did you feel that you had to be a part of this? And I think for a lot of us, the decision was, `No.'"

Bush served but avoided going to Vietnam by landing a coveted position in the Texas National Guard. Former Texas Lt. Governor Ben Barnes tells FRONTLINE, "I made a call because a friend asked me to allow young George Bush to be considered for the National Guard. His father was a congressman. And that would be the ... reason probably, that I made the call." [Editor's Note: Barnes is involved in raising money for the 2004 Kerry campaign.]

Bush relished his stint with the Guard, where he had been trained as a pilot. "I think he was on a high at that point," says close Bush friend Doug Hannah. "He was a pilot, he was flying…and clearly enjoyed the aura of walking around in a flight suit and being a flyboy. He was pretty proud of himself."

Following the Vietnam War, Kerry—now decorated with three Purple Hearts, a Silver Star and a Bronze Star—would achieve national attention as an anti-war activist, testifying in 1971 before the Senate Foreign Relations Committee and famously asking, "How do you ask a man to be the last man to die for a mistake?"

Kerry would attempt to build on his notoriety with a run for national office. "The Choice 2004" highlights his first congressional campaign. One month before the election, Kerry led polls by a two-to-one margin. "John's campaign was like the Dean campaign," says Tom Vallely, then director of the campaign's field operations. "We just had sort of the divided country, and a lot of people with John." But the editor of the local Lowell Sun newspaper would turn the tide with an anti-Kerry campaign.

"Day after day, they…printed full-page editorials that were treated like hard news about John Kerry in Vietnam, John Kerry the carpetbagger, John Kerry the radical, John Kerry being arrested," says David Thorne, Kerry's closest friend and former brother-in-law. Perceived as a carpetbagger who tried to exploit anti-war sentiment for his own political gain, Kerry was rejected by voters in Massachusetts' fifth district.

In 1978, Bush would also run for Congress. And like Kerry, he would lose his first campaign. Kent Hance, who won the race, tells FRONTLINE, "[Bush] wasn't as much of a creature of West Texas as I was. He had been at Andover, and he had been at Yale and Harvard. And with the people in that district, they felt like people in Yale and Harvard had made a lot more problems for them than they'd ever solved."

"The Choice 2004" continues as Bush and Kerry return to politics—this time successfully.

Bush had helped guide his father's winning race for the presidency in 1988, in part by recognizing the power of the evangelical Christian vote. Doug Wead, a campaign advisor to President George H.W. Bush in that election, tells FRONTLINE, "Sometimes, when he and I were talking or working over a memo, you could just see the light bulbs go off in his head….When we'd talk about the numbers and where they were, he'd just about salivate: `Wow, I could win the governorship of Texas with just the evangelical vote.'"

In 1994, Bush would run against a popular incumbent, Ann Richards. "I would say that George Bush's organization [was] the toughest I've ever seen," she tells FRONTLINE. "When I got up in the morning, I could be sure that Karen Hughes or the chairman of the Republican Party was gonna have something negative to say about anything I had done. And it was like a steady drip, drip, drip on a stone." "The Choice 2004" examines the hard-ball tactics the Bush campaign used to get him elected to the governorship.

Ten years earlier, John Kerry had also won office, as a senator from Massachusetts. In 1996, he would face a strong challenge to his senate seat from the state's popular Republican governor, William Weld.

Weld was a formidable opponent, and the race was a close one. Still, even after falling behind in the polls, Kerry would ultimately hold on to his seat. "We were landing pretty good punches in the '96 campaign," Weld tells FRONTLINE. "And [Kerry] reared back on his hind legs and punched back. He's not an effete preppie. You know, he does have the aristocratic background and manner of speaking. So you could be misled into thinking, `Here's a preppie. I'm gonna make mincemeat out of him.' And you'd be mistaken if you thought that."

Ultimately, "The Choice 2004" returns to the 2004 campaign and the issues that divide the nation and define the candidates, as well as the one issue that may decide the election: the war in Iraq and the ongoing threat of terrorism.

"[Bush and Kerry] come out of a severe split in the world they grew up in," says Nicholas Lemann. "And as a result, they represent very different policies for the United States government. Kerry will govern tremendously differently from Bush. Kerry will clearly try to get the United States into a more cooperative position with the rest of the world. Kerry seems to take government very seriously—he wants to serve, serve not just in the military sense, but in the government sense.

"I think Bush is more ambitious than Kerry," continues Lemann. "You feel that Bush really wants to change the world in a fundamental way. He really wants to be, you know, what they call a transformational president. If you want to be a really transformative president, you have to really push the edge of where foreign policy can go, both in foreign policy and domestic policy. If you're a moderate, you don't leave as big a footprint. I think this is a president who wants to leave a really, really big footprint."