To dispel notions that Bush might push him out of the contest, McCain said he was sure to stick with the race at least through Super Tuesday, a key date when more than a dozen states, including New York and California, will hold presidential primaries.

"This campaign will continue to March 7 no matter what," the Arizona senator said.

McCain joked with reporters about his decision to bypass today's Iowa caucuses, where Bush had a healthy lead in the polls over the rest of the GOP field.

McCain is tied or leading Bush in New Hampshire in most polls, and the Bush campaign hopes a strong showing in Iowa will help neutralize McCain. But McCain expressed no regrets over his strategy.

"People of New Hampshire don't pay a great deal of attention to what happens in Iowa," he said.

With the primary campaign shifting late tonight from Iowa to New Hampshire's primary on Feb. 1, McCain was firming up plans for a crucial week. They included the 30-second TV spot in which an announcer intones, "as a Navy pilot and POW he's seen the horrors of war. As a senator, he's already one of the nation's leaders in knowing how to keep the peace."

"If America is to lead, then America's leader must be prepared for that challenge," McCain says in the ad. Although it doesn't mention Bush, the spot takes aim at his limited foreign policy experience as Texas governor and his military service, which was a stint in the Texas National Guard during Vietnam with no combat.

The average New Hampshire voter will see the commercial six or seven times during its run, said campaign strategist Mike Murphy.

McCain was already making plans to fly out of New Hampshire hours after the polls close for the next battleground, South Carolina. The campaign is working on a South Carolina rally in the wee hours of Feb. 2, possibly around 2 a.m., a senior campaign official said.

The campaign also started a new ad in that state today featuring Rep. Mark Sanford Jr., R-S.C., calling McCain a "conservative reformer" like Ronald Reagan and a leader in fighting special interest influence.

Asked what would make him a better leader than Bush, McCain said, "Everything I've done legislatively, everything I've done in my life, but most importantly, I think I can articulate the vision to take on the next century and beyond.

"If I didn't think I was better prepared than Gov. Bush, then I wouldn't be contesting the election," he said.

The big push comes as McCain is fighting fatigue. McCain, 63, has said he plans to make this his first and last presidential run. Unless he pulls an upset and wins the White House, that is.

"I would never do this again. I'm too tired," McCain, R-Ariz., told reporters who surrounded him on his campaign bus Sunday, as he fueled his energy with several fists full of candy and his umpteenth cup of coffee. "I think it's fun once. I don't see how it's fun twice."

His wife, Cindy, who had just gotten off a cellular phone after speaking with one of their daughters, piped up, "You've got my vote."

There's not much time to rest between town hall meetings, television commercials and preparation for Wednesday night's debate here.

All the other candidates were making final campaign swings through Iowa in advance of tonight's first-in-the-nation nominating caucuses.

But lacking an organization in that state and support for his positions on some agricultural issues, McCain is staying back East. After the caucuses end tonight, he planned a rally at Dartmouth College.

Today also marks McCain's 100th town hall meeting, a staple of his campaign that began with handfuls of people attending and now draws several hundred each time.

Fielding questions on a host of domestic and foreign policy issues wears McCain down a bit. At one point he mixes up his rhetoric on abortion and adoption, then forgets the second part of a query by another member of the audience.

But that's nothing compared to the toll his and his wife's absence takes on their seven children, who are staying home in Arizona, McCain said.

"It's very, very hard on our kids," McCain said.