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The rivalry between Wesley Clark (search) and John Kerry (search) is more than two Democrats vying for the party's nomination -- it's Army versus Navy, general versus lieutenant, West Point grad versus enlisted.

The two veterans are counting heavily on their old military buddies to provide crucial support Tuesday in primaries in Arizona and South Carolina, which have more than 1 million veterans between them. Recognition of the "band of brothers" (search) is a constant at their campaign events -- and so is winning over the hearts and minds of those who wore the uniform.

"I found the enemy, and the enemy found me," Clark says at each appearance, often to laughter. "I was hit four times and spent three months recuperating. I got my Silver Star (search) and my Purple Heart in the mail when I was still in the hospital."

Clark graduated first in his class at West Point (search) and went to Vietnam as a company commander. In a 34-year career, Clark rose to become the four-star general overseeing NATO and U.S. troops in Europe during the Kosovo conflict. He makes repeated references to his Army service in his stump speech, and his events are typically in or near communities with a large military presence.

At every appearance, Clark invites the veterans in the room to stand and be recognized. Anecdotes about his military service, while self-deprecating at times, allow him to illustrate both his background as "just a soldier from Arkansas" and his readiness to deal with national security as commander in chief.

Kerry, a Navy lieutenant on a swiftboat, also returned from Vietnam with a Silver Star, three Purple Hearts and a Bronze Star (search). His life then took a different path. He became a vocal opponent of the Vietnam War (search) and launched a career in politics, entering Congress as Massachusetts' junior senator in 1985.

A military presence is never far from the Kerry campaign. He announced his candidacy in Mount Pleasant, S.C., across the bay from Charleston and with an aircraft carrier as a backdrop. A group of Vietnam veterans with whom he served follow him to most stops, manning phone banks and appearing in television commercials for Kerry.

Kerry routinely asks veterans in the crowd to raise their hands, and he thanks them for their service. When an elderly man felt faint at a rally Sunday at the Fargo Air Museum in North Dakota, Kerry left the stage to lend assistance.

"He's OK," he reassured the crowd. "He's a World War II vet and his legs aren't what they used to be."

So far, in voting in at least one state, Kerry has outshone the four-star. Exit polls in New Hampshire showed that veterans preferred Kerry to Clark by nearly a 2-to-1 margin, numbers close to the overall results in which Kerry won the primary and Clark finished a distant third.

Kerry's victory could tip the balance in his favor in Arizona, said Fred Solop, a political science professor at Northern Arizona University. More than 15 percent of the adult population in Arizona are military veterans.

"Momentum is on his side, and veterans are an important constituency in that regard," Solop said. "Veterans in New Hampshire weren't splitting their votes -- they were, by and large, supporting Kerry, and I think you will see the same in Arizona."

Both Clark and Kerry have asked veterans for help in fund-raising, organizing and getting out the vote. But Clark created a stir when he suggested that Kerry's experience as a lieutenant could not match his own as a four-star general.

"That's something you say at the officers' club, not on the campaign trail," said Dick Harpootlian, the former chairman of the South Carolina Democratic Party, who pointed out that in the South, "you're going to have a heck of a lot more retired enlisted than retired generals."

A Kerry backer, Sen. Ernest Hollings of South Carolina, was even more blunt, saying, "We're going to teach that fellow in South Carolina that there are more lieutenants than there are generals."

The South Carolina primary is open to all voters regardless of party affiliation. Recent polls show John Edwards and Kerry battling for the lead, with Clark barely in double digits. Scott Huffmon, an assistant professor of political science at Winthrop University in Rock Hill, S.C., said Clark probably could appeal to the crossover votes, "but that shouldn't be the hook on which to hang his hat in terms of winning this on Feb. 3."

South Carolina has about 400,000 veterans, according to the most recent U.S. Census figures.