Every candidate makes mistakes. They're human; that's what they do. In the course of a campaign office seekers and their staffs will err. The question is who makes the fewest and the least damaging blunders. In a competitive race between qualified candidates, victory often goes to those who best overcome the imperfections of campaigns functioning under high stress and under the microscope. Thus, which among the leading Republican candidates for President will succeed in that paradigm?

A good question since the weaknesses of the three leaders - Rudy Giuliani, Mitt Romney, and Fred Thompson - were on display last week.

1) Rudy Giuliani - several data points show his campaign may be living off his positive name ID as "America's Mayor" and that he's not wearing as well with likely Republican voters as they assess him as a Presidential candidate.

Gallup poll analysis showed that while he continues to lead the field, his support is potentially frail. 91% of Republicans proclaim themselves familiar with Giuliani (translation: they know who he is and have some impression of the man). In contrast, only 64% and 56% say likewise about Mitt Romney and Fred Thompson respectively. That leaves a lot of room for growth from those two.

Among those familiar with all four leading candidates Giuliani actually trailed Thompson 25% - 33% and was only nine points ahead of Romney (16%). Among those not familiar with all four, Giuliani led McCain 38% - 18%, with Thompson and Romney trailing. The obvious inference of the numbers when considering what may happen as likely primary voters acquaint themselves with the field further is not good for Giuliani.

A recently released Pew poll also showed Romney and Thompson with large room for growth. Likewise, the survey also showed Giuliani holding a wide yet comparatively shallow base of support.

A quick review of the early states where candidates have been campaigning the most shows a similar mixed bag at best for Giuliani, in contrast to his firm national lead. He's trending down in Iowa. He has at least stabilized in New Hampshire with more aggressive campaigning and with an assist from McCain's collapse, but still trails Romney by a significant margin. He still in reasonably good position in South Carolina despite Thompson's rise, again with an assist to McCain's fall as well as to Romney's lag in the state. He also looks solid for now in Florida though the trend line is still not good in the long-run.

The question to watch with Giuliani is how effectively and with what themes does he sell himself as a Presidential candidate? Absent a resonant message he looks less formidable beneath the veneer of his high national poll numbers. But he's got several months to prove himself to likely primary voters and has been campaigning better the last several weeks.

2) Mitt Romney - Ah, the flip-flop. The Washington Post and ABC eagerly reported last week on a perceived such abortion blunder. They bungled the story, however, as fellow MSMer Marc Ambinder pointed out.

Several prominent conservative bloggers also weighed the charge and found the media judgment, not Romney, in error. Kathryn Lopez deconstructed the issue at the Corner (with a concurrence from Jim Geraghty). Jennifer Rubin chimed in as well, as did Matt Lewis at Townhall, fairly noting that Romney could have been clearer on the topic.

The flip-flop theme is perhaps the most dangerous story line for Romney if it resonates. The threat is particularly severe given the lack of knowledge about Romney for many voters, as indicated in the Gallup and Pew polls cited above. If what voters learn of Romney before early next year comes through the lens of perceived flip-flops as opposed to his campaign message then he will be in an exceedingly difficult, if not impossible, position. The ability of he and his campaign staff to avoid and mitigate possible outbreaks of the motif is essential. Valid or not, future such stories are potentially devastating to his candidacy.

3) Fred Thompson - When the phrase "Worst Presidential Rollout Ever?" is being employed with any seriousness that's not a good thing.

Thompson's stall in national and early state polls is obvious and a bad narrative continues to develop around his campaign before it even becomes official. It's hard to see how it looks good for a candidate who looked to be on the cusp of jumping into the race after the Republican debate on June 5th to belatedly get up on the debate stage September 27th, having avoided two additional debates in the interim.

Meanwhile, media attention to his "testing the waters" efforts has not been terribly helpful. Fox News coverage of his August trip to Iowa was not good, for reasons that seemed avoidable. When fairly or not you've been pegged as a "lazy" candidate, don't be the only Presidential candidate to ride around the Iowa State Fair in a golf cart...and definitely don't take a half hour to recoup after only one hour pressing the flesh.

Similarly, it simply won't work for a former actor who is expected to be able to deliver prepared material well to receive noticeably bad reviews for a major speech:

It's also troublesome to see unforced errors before a candidate is even official. His blog post about Giuliani's 2nd Amendment record, no matter how indirect and legitimate, was described as "an odd and early direct shot." The specter of going negative before one announces is indeed peculiar. Never mind that Thompson losing yet another staff member before even being an official candidate is an eyebrow raiser.

Individually, none of the stories is terrible. In sum, they paint the picture of a candidate who may not be ready for prime time. It would be a shame if that happens given his willingness to talk about big issues. Thompson's clear-voiced conservative commentary is perhaps his best asset and his ability to influence the Republican primary debate could benefit whoever turns out to be the nominee. But Thompson simply has to do better on the trail. Agree with Giuliani and Romney or not, they are strong, polished candidates thanks to their experience campaigning throughout this year.

The Republican field remains wide open, giving each of the three major candidates discussed above the chance to break through if they can overcome the inevitable travails of the campaign trail. Each candidate has unique strengths and weaknesses that make them impressive though imperfect contenders. Who mitigates those weaknesses the best? Whose strengths overcome inevitable missteps? How all that unfolds should make for a compelling spectacle in the coming months.

UPDATE: amazing. Add yet another to the long line of staff departures from the Thompson campaign before it is even official.