Mitt Romney snapped back from South Carolina with a Florida primary victory that took advantage of a more diverse electorate, re-established his image of electability and economic leadership, and demonstrated his organizational firepower in attracting - and retaining - early-deciding voters.

Far fewer voters made up their minds in the Florida campaign's closing days than in any previous GOP contest this year - and Romney won his largest share of those who did. His final barrage of ads may have helped both to limit the number of late-deciding voters, and to stem defections in this group.

The exit poll, analyzed for ABC by Langer Research Associates, found that Romney had other advantages - much more positive personal appeal than his top competitors; a sharp gender gap for the first time this year, with far greater support among women; fewer evangelicals, a group in which he's struggled; lots of seniors; and, in another first for the GOP in 2012, a substantial number of minority voters. Mainly Hispanics, they backed Romney by more than double his margin among whites.

Yet, while the result pulled Romney back to his strong New Hampshire showing, there was enough in the results to give Newt Gingrich a continued source of ammunition. A substantial 41 percent of Florida voters described Romney's positions on the issues as "not conservative enough"; among all non-Romney voters, 67 percent said so. Gingrich, indeed, won "very" conservative voters by 42-30 percent, won the strongest anti-abortion voters by 15 points and won strong supporters of the Tea Party political movement - more than a third of all Florida primary voters - by 12 points.

In a more general kvetch (and possible nod to ex-Gov. Jeb Bush), nearly four in 10 voters said they'd like to see someone else run for the nomination. But Romney nonetheless prevailed on enough personal measures to stick it to Gingrich - and to overcome negative-campaigning criticism at the same time. Sixty-five percent of Florida voters said they'd be satisfied with Romney as the Republican nominee - well more than said the same about Gingrich or Rick Santorum, 53 percent apiece. And more, a broad 76 percent, expressed a favorable opinion of Romney overall - compared with 55 percent for Gingrich.

Gingrich also may have trouble sustaining another argument, the claim he'd have run a closer race without Santorum in the contest. To the contrary, Santorum's voters were more apt to see Romney favorably than Gingrich, 60 percent vs. 49 percent, and about equally apt to say they'd be satisfied with either of them as the eventual Republican nominee.

Further, while Gingrich tried to paint Romney as out of touch with the common man and woman, Romney led him, albeit slightly, on this score - 34 percent said Romney best understands the problems of average Americans, vs. 26 percent for Gingrich. Notably, that leaves 31 percent who picked Santorum or Paul (19 and 12 percent, respectively) on this attribute, making it a weak spot for Romney and Gingrich alike.

Elsewhere, though, Romney shone. Fifty-four percent of voters called him best suited to defeat Barack Obama, vs. 28 percent for Gingrich. And among those who selected defeating Obama as the single most important candidate quality - 46 percent of the electorate - 58 percent voted for Romney, rivaling his New Hampshire showing among beat-Obama voters, and landing him 26 points ahead of Gingrich in this group.

The advantage on electability more than negated Gingrich's strong lead among voters most focused on a "true conservative," since there were far fewer of them, just 14 percent. Gingrich's lead over Romney among voters mainly focused on experience was just in the single digits. And among the 16 percent looking chiefly for the candidate with "strong moral character" Romney crushed Gingrich, 44 percent to 7.

For the first time this year there was a striking gender gap in the results; men favored Romney by just 6 points, 41-35 percent, over the thrice-married Gingrich (whose competitiveness was, more narrowly, exclusive to married men), while women supported Romney by more than 20 points, 51-28 percent.

Another notable result was the number of early deciders in this contest. Four in 10 came to their decision in December or earlier, before any of the barrage of campaign ads hit the airwaves. And those early deciders favored Romney over Gingrich by more than 2 to 1, 56 to 25 percent.

On the flipside, only 28 percent decided in Florida in the last few days - about half the number of late deciders as in South Carolina, 55 percent. Romney won these late deciders, but by a narrower margin, 45-32 percent.

The volley of campaign advertisements - predominantly by Romney, and generally characterized as negative - seems to have helped him. Romney won voters who said the campaign ads didn't matter to them, by 10 points. His margin grew among the four in 10 who said the ads did matter, to a vast 60-24 percent.

Romney also did better with late deciders than in any other state, and there were fewer of them, suggesting the ads may have kept early voters at his side. And there was no apparent negative effect.

Asked who ran the "most unfair campaign," voters divided evenly between Romney and Gingrich.

Among other results:

• Evangelicals accounted for 47 percent of voters, up 8 points from their share in 2008 but still far below their 65 percent in South Carolina. And, as in New Hampshire, Romney did better with them: He split evangelicals evenly with Gingrich, after losing them by 2 to 1 in South Carolina. Among non-evangelicals, meanwhile, Romney won in Florida by 54-26 percent.

• In another example of a more diverse electorate, more than three in 10 Florida voters were Catholics, compared with 13 percent in South Carolina. Romney won them by 26 points. In another, after contests in which 98 or 99 percent of voters were white, that proportion eased to 82 percent in Florida. Romney won whites by 12 points - and won nonwhites, mainly Hispanics, by twice that margin, 25 points.

• Seniors accounted for more than a third of Florida voters, above their 27 percent in South Carolina. They've been a consistently better group for Romney, and while he prevailed among all age groups, his support cracked 50 percent among seniors, a feat in a four-candidate race.

• Romney also again did particularly well among better-off voters, winning those with $100,000-$200,000 incomes by 16 points and the few with incomes more than $200,000 by a vast 61-23 percent, his highest support in any demographic group. Romney also won voters with less than $50,000 incomes, albeit by a closer 43-31 percent. He showed weakness, though, among the nearly three in 10 who said they're falling behind financially, splitting those voters with Gingrich.

• More than six in 10 voters said the economy was the most important issue, No.1 by far, as in previous contests. And among those who picked it, Romney beat Gingrich by 52-29 percent. After losing them to Gingrich in South Carolina, that's Romney's best showing to date among economy voters - better even than in New Hampshire.

In the end, while Romney's improvements over South Carolina occurred across the board, they were most substantial in centrist groups. Romney improved by about 10 points among strong conservatives and strong Tea Party supporters, but by 20 points among "somewhat" conservatives and milder Tea Party supporters, and by 26 points among moderates. He also scored his broadest support to date among self-identified independents (admittedly a smaller group in Florida's closed primary), winning them over Gingrich by 40-27 percent in a state where Paul largely stood aside.

The Florida results put Romney in a strong position to dominate the campaign narrative in the upcoming lull, with no major primaries until the end of the month. The questions are whether he can this time maintain his regained momentum - and, more broadly, whether he can win the Republican nomination without winning the most strongly conservative voters at the party's core.

By Gary Langer, with Julie Phelan, Gregory Holyk, Damla Ergun and Erica Berlin.