"Never underestimate what a determined soldier can accomplish when he's fighting for his country," the retired Army general said.
Clark and North Carolina Sen. John Edwards (search) were vying for third place in New Hampshire, each with about about 12 percent of the vote.
Clark entered the race late with no experience in elective politics, but gained ground quickly by emphasizing his military background and leadership experience. Lately, he has been offering himself as the true outsider and emphasizing his Southern roots and humble background to argue that he is both electable and sympathetic to the struggles of working families.
"Four months ago, we weren't even in this race. We had no money. We had no office. All we had was hope and a vision for a better America," he said. "We came into New Hampshire as one of the Elite Eight. We leave tonight as one of the Final Four."
Clark performed best among voters who thought national security and terrorism were the top issues in the campaign. But little more than one in 20 thought those were the top issues, according to the poll of 1,848 voters conducted for The Associated Press and the television networks by Edison Media Research and Mitofsky International.
Clark finished second to Kerry among voters who thought experience was the most important candidate quality, the poll showed.
Clark didn't compete last week in Iowa and climbed as high as second in some New Hampshire polls. But some eyebrow-raising remarks took their toll, and advisers conceded Clark lost much of the momentum he enjoyed while the rest of the field was in Iowa.
Clark nonetheless insisted his showing Tuesday laid the groundwork for future success.
"We're heading south. We're heading west. And we're not slowing down until the last buzzer sounds," he told a crowd of pom-pom waving supporters. "Today was just the first battle in our campaign to take America back."
Clark was flying to South Carolina on Tuesday night and planned to start his day there before hitting Oklahoma, New Mexico and Arizona later Wednesday. He has been running commercials in five of seven states that vote Feb. 3, and his advisers say he will continue to purchase significant air time in South Carolina this week while pumping in considerably more money than he had been in Arizona, New Mexico, Oklahoma and North Dakota.
"Wes Clark comes out of New Hampshire standing," said George Bruno, Clark's New Hampshire campaign chairman. "He'll go south with strong winds at his back."
In the weeks leading up to the primary, Clark stirred controversy with comments that the Sept. 11 attacks were preventable and that he opposed any legal restrictions on abortion at any point in a pregnancy. He later said he supported a woman's right to have an abortion "as modified by" a 1992 court case that allows states to impose limited restrictions.
He also backtracked on Monday after saying that he was the only candidate who grew up poor, conceding that several other candidates' families also struggled to make ends meet.