(TAMPA, Fla.) -- Mitt Romney will win the Florida Republican primary, ABC News projects, based on the exit polls and analysis of the vote in so far.
Newt Gingrich will be second, Rick Santorum third and Ron Paul will place fourth, ABC News projects.
Romney appeared to win most of the state's southern and central region, while Gingrich's support was concentrated in the north.
The former Massachusetts governor's debate performance last week and negative ad campaign against chief rival Gingrich played a key role in his victory in the Sunshine State.
Preliminary exit polls found that Republican voters were heavily influenced by the debates and campaign ads that dominated the Florida airwaves for weeks. As in Iowa and South Carolina, voters were looking for the candidate who has the best chance to defeat President Obama. About two-thirds of Florida voters in these preliminary results said they would be satisfied with Romney as the Republican nominee.
Romney jumped into Florida well before any of his competitors, launching TV ads even before the South Carolina primary. That move may have helped him, as exit polls found that four in 10 voters made up their mind before the start of the month, much more than in South Carolina.
Both candidates and the super PACs supporting them have spent millions of dollars in attack ads, but the former House speaker was far outweighed by his chief rival when it comes to spending.
Romney's campaign spent nearly $7 million on television ads leading up to the primary, more than six times that of Gingrich, whose campaign spent about $1 million.
The super PACs have even outspent the campaigns. The group supporting Romney, Restore Our Future, spent a whopping $8.5 million on ads in Florida, while Winning Our Future, the super PAC backing Gingrich, spent about $2.2 million.
Neither Rick Santorum nor Ron Paul, the other two candidates in the race, are on the airwaves. Both were instead focusing on Nevada, the next voting state.
Romney was actually on the airwaves more in 2008, when he lost the state to Sen. John McCain. But in this race, he dominated the airwaves against his rivals, airing almost 13,000 ads on broadcast television across the state, as of Wednesday, Jan. 25 -- much more than Gingrich and his support groups, which together have aired about 200 spots, according to the Wesleyan Media Project.
Ninety-two percent of all TV ads aired in the Sunshine State over the last week were negative, mostly targeted at Gingrich, according to Kantar Media Campaign Media Analysis Group.
Gingrich had made his mark by stellar debate performances that set him apart from other candidates. It was one of the reasons why he won by an overwhelming margin in South Carolina. But that changed last week as Romney aggressively attacked Gingrich on his past connections to Freddie Mac and his immigration ads.
Fifty delegates are at stake in today's primary, an important number for Romney.
Copyright 2012 ABC News Radio