List of Republican 2012 Opt-Outs Begs 'Who'd Want to Be President Anyway?

ABC News' Devin Dwyer (@devindwyer) reports:  Republicans who flirted with running for president in 2012 -- and decided not to try -- showed little appetite for the relentless demands and punishing grind of a campaign.  Their candid characterizations now make one wonder who would.      Former Arkansas Gov.  Mike Huckabee, who ran an insurgent campaign in 2008 and had led in many 2012 pre-primary polls, said he wasn't ready to be pushed "to the limit of his...human capacity." 

Indiana Gov. Mitch Daniels, who lamented he couldn't resolve family "considerations," said a campaign is "not a mountain you jump off of by yourself."

And Mississippi Gov. Haley Barbour eschewed the "all-consuming effort, to the virtual exclusion of all else," of a campaign -- which his wife, Marsha, said "horrifies" her.

"It takes your whole life. It takes everything you know and everything you've got," said Richard Ben Cramer, author of "What It Takes: The Way to the White House," of being a presidential candidate.   "And they can never go back to what they called their life because the campaign changes them," he said.

So what type of person takes the presidential plunge anyway?

Someone with an insatiable hunger for the "number one job in the world," Cramer said. 

"All of these guys are such 'winners' in life that when they look in the mirror that's what they see," he said. "If you look at the background of candidates for president, on the whole, these guys are like heavy lumps of iron, and the whole world has bent around them since they were babies.

"They can be excused for thinking this is the job for them," he said.

Research shows presidential candidates also share an above-average desire for power.

"They like the idea of exerting influence both on reality itself and other individuals," said Chris Federico, director of the Center for Political Psychology at the University of Minnesota.

They have a "need for achievement, a need to achieve excellence in some realm," he said. "And some are after affiliation, to have connections with other people."

Ultimately, experts say, the decision of whether or not to run for the White House -- at once deeply personal and strategic -- boils down to what candidates and pundits describe as a gut feeling, a "fire in the belly."

"It's a huge investment that takes an incredible amount of time and dedication, all when the odds aren't all that good either," said Vanderbilt University political scientist John Geer.

"It's clear that guys like Pawlenty and Romney have a certain level of energy and ambition and desire to make a difference. And that's good," he said, "because if you're going to be president, you will be working constantly."