WASHINGTON - As Sen. John Kerry tries to fend off charges that he is an elite and aloof Massachusetts liberal who's soft on national security issues, he underscores his life-defining experiences as a Navy patrol boat skipper in Vietnam.
As he struggles to overcome a perception that he is wooden and passionless, the presidential candidate looks to his former crewmates, who have offered vivid, emotional testimonials to their one-time commander's heroism on the muddy waters of the Mekong Delta.
And when Kerry needed a core group of campaign workers in such states as Iowa, where organized labor backed his Democratic rivals, he summoned his fellow veterans, most of them gray-haired grandparents, who left homes and jobs to campaign for an old comrade-in-arms.
Kerry's Vietnam service was the formative event of his life and character, as it was for so many of his generation. It is also one of the linchpins of his presidential bid. His searing combat experience - which earned him a chestful of medals and triggered his high-profile anti-war activities once he came home - has provided much of the muscle behind Kerry's quest to unseat a wartime president.
"His Vietnam experience is the very heart and soul of the entire campaign," says presidential historian Douglas Brinkley, author of Tour of Duty, a new book about Kerry's Vietnam service.
After winning Tuesday's New Hampshire primary, Kerry, 60, told a cheering crowd in Manchester that his victory belonged "in a special way" to the veterans who joined his campaign.
"They helped to lift us up from the lowest points to the point where we are today," Kerry said, joined on stage by several of his crewmates and triple combat amputee Max Cleland, the former Georgia senator.
"In the hardest moments of the past month, I depended on the same band of brothers that I depended on some 30 years ago," he said.
Kerry is not the only veteran among the Democratic hopefuls - Wesley K. Clark, a retired four-star general and former NATO commander, has also built his candidacy around his military and national security expertise. But along with mentioning his war experiences at nearly every campaign stop, Kerry has staged events specifically for veterans.
Two days ago, for example, at a town hall meeting for veterans in Columbia, S.C., he pledged to be a "veteran's veteran" as president and vowed to make the concerns of service members, past and present, his "personal mission."
Peppering his speeches with talk of "the promises that soldiers make to each other" and "the lessons of the wars we have fought," Kerry uses his military background - combined with his political experience - to make the case that he is uniquely qualified to lead the nation in the dangerous post-9/11 world and to offer a contrast with President Bush's Vietnam-era service in the Texas Air National Guard, which was not deployed to Southeast Asia.
Kerry gleefully mocks Bush's donning a flight suit and landing on an aircraft carrier to declare success in the war against Iraq. "I know something about aircraft carriers for real," Kerry says often, a guaranteed applause line with Democratic audiences.
Similarly, Kerry has used "Bring it on" - alluding to a controversial phrase Bush used in July to taunt U.S. enemies in Iraq - as a campaign slogan to express his eagerness to debate the president on national security issues.
Kerry has had unprecedented success in mobilizing veterans to work for his campaign. In Iowa and New Hampshire, the early-voting states that turned Kerry into the Democratic front-runner, veterans formed the backbone of his campaign. They knocked on doors and operated phone banks - at Kerry's Des Moines office, at least 50 percent of those making campaign calls were veterans on any given day.
In fact, though throngs of young Internet-savvy Howard Dean supporters descended on Iowa, they seemed to make little connection with voters there and in some cases were deemed a nuisance. Kerry's "Veterans' Brigade" received far less attention but was credited with a major effect on the race.
"A phone call from a supporter to a voter is like a call from a telemarketer, but a call from one veteran to another is like a call from a friend to a friend," says John Hurley, Kerry's national veterans coordinator. "The impact was just huge."
One of the most emotional moments for Kerry in Iowa - an event that some political analysts credit with humanizing a candidate who had been seen by some as a cardboard cutout - came when a 56-year-old Republican from Oregon, a former Green Beret who had been aboard Kerry's Swift boat 35 years ago, flew to Iowa to tell audiences how the young Lieutenant Kerry - wounded and under fire - had pulled him from the river and saved his life.
Now, many of Kerry's crewmates, as well as busloads of other veterans, are fanning out to states such as South Carolina, Missouri, Arizona and New Mexico that hold primaries or caucuses Tuesday to set up veterans' operations.
"He's created for himself a corps of troops who are moving from battleground to battleground, state to state, in a tireless effort to make John Kerry the president," says Brinkley, who heads the Eisenhower Center for American Studies at the University of New Orleans. "It's unique."
Several of Kerry's new ads airing in states with contests Tuesday, especially South Carolina and Arizona with large numbers of veterans, feature slow-motion footage of Kerry walking through the jungles of South Vietnam in helmet and flak jacket, holding an M-16 while, in a voice-over, a former crewmate praises his leadership: "When the bullets began to hit the side of the boat - the boom, the pow-pow-pow - we found out that John Kerry could lead."
Arizona Sen. John McCain, a Vietnam veteran and POW who challenged Bush for the Republican nomination in 2000, similarly looked to veterans when he needed to build a base outside the party establishment.
Although veterans and active military personnel tend to vote Republican by almost 2-to-1 - and, as a whole, are still likely to favor Bush over any Democrat - Kerry has had success with many of these voters because of the rise of national security concerns, say political analysts.
"If you're trying to appeal to this category, you'd rather be a Republican than a Democrat," says Duke University political scientist Peter Feaver. "But if you're a Democrat seeking out this vote, you'd rather it be 2004 than 2000."
Now that Americans have experienced terrorist attacks, says Feaver, Kerry is "exploiting the fact that it's unthinkable that a candidate could win the presidency without having convinced the American people that this person can be trusted to deal with terrorists."
Democrats believe, too, that Bush has lost support with some veterans - over his "Bring them on" challenge as American troops were fighting in Iraq, growing uneasiness about the war, as well as the president's efforts to overhaul the veterans' health care system, including shutting some hospitals and raising some health care fees.
In his appeals, Kerry points to his 19-year Senate career, in which he says he has fought for increased spending and improved programs for veterans.
Kerry enlisted in the Navy in 1966 just months before he was to graduate from Yale. After five months in the Pacific aboard the guided-missile frigate USS Gridley in late 1967 and early 1968, he trained to command the Navy's small Swift boats. Carrying a crew of about five or six, the gunboats were used to patrol the narrow waterways of the Mekong Delta and flush out the enemy.
He spent six months on the Delta's perilous rivers and canals, receiving a Silver Star and Bronze Star for gallantry. He also received three Purple Hearts.
Once back in the States, he joined the Vietnam Veterans Against the War and became a prominent anti-war spokesman, challenging the Nixon administration to end hostilities. The White House, in turn, sought to discredit him as opportunistic and politically ambitious, according to tape recordings of Richard M. Nixon and a top aide, H.R. Haldeman.
Kerry captured the nation's attention when, at a Senate hearing in 1971, he said to the assembled senators, "How do you ask a man to be the last man to die for a mistake?"
Conservatives have seized upon his anti-war activities and are already trying to portray them as anti-American and, as National Review Washington editor Kate O'Beirne wrote last week, "disgraceful" and "slanderous."
But others believe the full arc of Kerry's story - the fact that he both fought in the war and tried to end it - could work to his advantage, especially given the uncertainties surrounding the nation's invasion of Iraq.
Asked at a debate last month how he would feel as president if a veteran tossed away his medals - much as a young, shaggy-haired Kerry did when he hurled some of his ribbons at the steps of the Capitol - the candidate had a ready answer:
"The United States of America should only go to war because we have to. And if you live by that guidance, you'll never have veterans throwing away their medals or standing up in protest."