TAMPA, Florida — Measured in business, deliberative in politics, Mitt Romney has always taken the long view, and his coronation Thursday at the Republican convention caps a five-year run for the White House.

The 65-year-old has been gearing up for this moment since he stepped down as governor of Massachusetts in January 2007. Fourteen months later, he was the Republican also-ran as rival John McCain won the party's nomination.

But the experience offered countless political lessons for Romney's 2012 campaign, in which he bested conservative rivals, survived early gaffes, faced a barrage of negative ads and overcame doubts of core Republicans.

Several doubts still linger about Romney's financial dealings, his trouble relating to everyday Americans, his lack of foreign policy experience and President Barack Obama's critical advantage among women voters.

But Romney is a wizened, more focused candidate this year, experts said.

"He may have the nature of a long-distance runner who sets his eyes on the goal that's out there in the distance," Mike Franc, vice president for government studies at the conservative Heritage Foundation told AFP.

Running for president, however, is not a marathon but "a decathlon, with multiple skills needed for multiple challenges," Franc added.

Challenges piled up for Romney, beginning with the first state contest of the year.

Romney lost a January 3 nail biter in Iowa to rival Rick Santorum, the arch-conservative former senator from Pennsylvania, then got thumped by former House speaker Newt Gingrich in South Carolina.

In the next contest, Florida, Romney rallied, unleashing a barrage of attack ads on Gingrich. It was the moment that many perceived Romney to be in control of his primary destiny.

"Romney showed tenacity and discipline in the (Florida) debate and from that point on I don't think the nomination was really in doubt," said Matt Dickinson, a political science professor at Middlebury College.

It wasn't all smooth sailing. Romney lost three primaries in a row to Santorum, and many doubted whether Romney could carry the party base.

He also appeared out of touch in a series of gaffes, including when he said he was "not concerned" about poor people, and that his wife drives "a couple of Cadillacs" -- off-point remarks for a candidate who routinely highlights America's 8.3-percent jobless rate and says Obama has failed the economy.

But Romney outmaneuvered his more conservative rivals, and by May he had clinched the nomination, which will be formally announced Thursday at the Republican National Convention.

Professor Steffen Schmidt of Iowa State University said Romney, aware of the need to win over independent voters, adopted the pragmatic political art of "strategic shifting."

Portraying himself as a Christian conservative during the primaries, Romney now talks little about social issues like abortion, which he recently stressed he does not oppose in cases of rape.

Instead, his mission is convincing voters he will translate the business acumen which made him a multimillionaire into a recovery plan for America.

"What's surprising is that he has survived all of this, is the nominee of a very conservative GOP... and will likely get a big turnout from Republicans who don't like him very much," Schmidt said, adding that many conservatives "think he's a waffler who changes his mind for expediency."

The president has meanwhile put Romney on the defensive with ads attacking the challenger's record at private-equity firm Bain Capital, his refusal to divulge more than two years of tax returns, his mysterious overseas accounts, and his plan to give tax breaks to millionaires.

Romney made things worse with a dismal foreign trip that highlighted his lack of experience on the world stage.

Then Obama inadvertently presented a gift. "If you've got a business, you didn't build that," he said in July, speaking about entrepreneurs and the help they receive from government-funded infrastructure.

Romney seized on the comment, using it to pivot away from suspicion about his own record and fixate on Obama's big-government philosophy.

In late July Romney unveiled Paul Ryan as his running mate, the powerful House Budget Committee chairman intent on reforming entitlements and curtailing runaway federal spending.

Observers hailed the choice as one that would ensure a debate centered around big ideas and bring ideological clarity to Romney's campaign.

Campaign rallies swelled to the largest of his career, and while Obama was still leading in most polls, Romney has gained recently as he has pressed his case that the president's economic policies have failed.

"America can do better than it has been doing," Romney wrote in an op-ed in the Tampa Bay Times on Sunday.

"Decline is not our destiny. The 21st century can and will be an American Century. But to accomplish that we need to change course."