NEWINGTON, N.H. (AP) — From an airport runway on a cold New Hampshire morning, Republican Mitt Romney faced 2,000 supporters and delivered the same speech he had given the day before — three times on the day before, actually.

"I won't just represent one party, I'll represent one nation," the presidential candidate declared Saturday for the fourth time in 36 hours as swing-state Republicans cheered, most of them hearing his pledge for the first time.

The Romney stump speech, like that of his opponent, is a carefully crafted 15 minutes that opens a window into the strategy behind his second presidential bid. And for Romney, it is a constantly evolving tool that has shifted sharply in recent weeks to appeal to the political center.

Let there be no doubt that Romney, who once described himself as "severely conservative," is aggressively courting the narrow slice of undecided voters — largely women and moderates — who have yet to settle on a candidate.

From central Florida to central Iowa, the stories Romney tells in daily campaign stops have changed to include intimate personal details. The emphasis on his business career has been forgotten. And while he repeatedly jabs President Barack Obama, he devotes as much time to an optimistic vision for an America that would "come roaring back" under a Romney administration.

"Come walk with me. Walk together to a better place," Romney said Saturday with the confidence of a man who has used the line several times before.

The year before, Romney launched his presidential campaign in New Hampshire with a very different message. At the time, he referenced his 25-year business career in almost every speech, suggesting he was uniquely qualified to repair the nation's ailing economy.

It was all economy, all the time.

"This, for me, is not about the next step in my political career," the former Massachusetts governor who also ran for president in 2008 told a New Hampshire audience in September 2011. "I don't have a political career. I spent 25 years in business."

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But three days before Election Day, Romney the businessman had completed the journey to becoming Romney the politician.

He drew heavily from his experience in Massachusetts, devoting just a few sentences to his business career. He cited his work to cut taxes, create jobs, cut the deficit, improve education. And above all, he emphasized his ability to work with the Democrats who dominated state politics.

"Instead of attacking each other, we went to work to try to solve our problems," Romney said.

While heavily scripted, the daily stump speech also offers the occasional insight. Romney often slips dry humor into his speeches along with awkward words that sometimes raise eyebrows. He loves to begin sentences with, "In the final analysis," references "quartiles," and often proclaims, "Wow!"

On Saturday he joked that his New Hampshire supporters should "harangue" his friends. Later Saturday in Iowa, he noted that Sen. Chuck Grassley recently hit a deer with his car and asked, "Was it delicious?"

Romney has never possessed the same charm at the podium that allowed successful campaigners in the past — Ronald Reagan, Bill Clinton and Barack Obama among them — to connect with voters. But, in the speeches themselves, Romney has tried to address that weakness. This week he has repeatedly declared that "talk is cheap."

He also uses his speeches to address the regular criticism that he's not offering enough specifics. In virtually every rally since late summer, he outlines a five-point plan to get the nation's economy going. It's a general list of talking points that is largely in line with Obama's, albeit with different focuses.

First, Romney says he'd push an energy agenda that focuses on oil, gas and coal. He'd then adopt a trade policy that opens markets in Latin America and cracks down on China. The Republican also supports training and education programs that work around teachers unions. He'd also get the nation "on track" to a balanced budget. And finally, he would "champion small business."

Perhaps most striking is the shift in the personal stories he tells to help connect with voters.

For several months, on a near-daily basis, he shared underdog stories of oilmen and food industry magnates. In recent weeks, he has spoken instead about Boy Scouts who watched a space shuttle explosion, talked of a sister who has raised a child with Down syndrome and devoted a special mention to single mothers.

"I think of all the single moms who are scrimping and saving to make sure they have a good meal on the table at the end of the day for their children," he said this week. "We're a nation of people with great hearts who care very deeply about things bigger than ourselves."