It wasn't supposed to be this way. John McCain was the presumptive Republican front-runner, the next in line for the nomination in a party that historically respects hierarchy. Now, he's trying to revive his troubled campaign. He is making the case for his candidacy by stressing his decades of experience in wartime and Washington and claiming he has the will to make tough, and sometimes unpopular, choices to heal the nation's woes. "I am qualified. I am ready to serve. I need no on-the-job training. And I have the vision and capability," the four-term Arizona senator, ex-Navy pilot and former Vietnam prisoner of war, said Wednesday after formally declaring his second attempt to win the White House. A loser in 2000 to George W. Bush, McCain chose to officially enter the presidential race in New Hampshire - home of the primary that marked his political high point of his previous bid. He selected Prescott Park, which sits across the Piscataqua River from the Portsmouth Naval Shipyard. As McCain talked of the nation's challenges at home and abroad, the shipyard served as a backdrop and a reminder of his military past. "I know how to fight and how to make peace. I know who I am and what I want to do," he said in his speech. "I'm not running for president to be somebody, but to do something; to do the hard but necessary things, not the easy and needless things." He repeated his pitch later in Manchester, N.H., standing under an umbrella as rain pelted an enthusiastic crowd of a few hundred. When a protester interrupted, McCain diverted from the script. "This is what free speech is all about!" he shouted, drawing cheers when he invoked the state's motto: "Live free or die!" He then headed to South Carolina and in coming days will appear in Iowa, Nevada and Arizona as part of a four-day campaign tour. Simply a formality, the events did, however, give McCain an opportunity to lay out his vision for the country's future and jump start his campaign after months of struggle. He had spent years building an unrivaled national organization and positioning himself as the inevitable GOP nominee - only to see his campaign falter. "It's John's last chance to make a first impression again," said Ken Duberstein, a White House chief of staff under President Reagan. "He has to wipe the slate clean from the last several months. That's easier said than done, but I think he has the chance to do it." McCain's popularity has fallen in national polls; he trails former New York City Mayor Rudy Giuliani. He came in a disappointing third in fundraising and cash-on-hand among Republicans in the first test. Rival Mitt Romney, in single digits in most polls, finished first. McCain revamped his finance operation and trimmed staff as a result.