U.S. Republican presidential candidates are hoping a victory on Tuesday in Florida's primary election will give them a major boost in their bid for their party's nomination.
Opinion polls indicate Arizona Senator John McCain and former Massachusetts Governor Mitt Romney are in a tight race for first place in Florida.
In recent campaigning, Romney has attacked McCain's record on energy, immigration and campaign finance reform.
In return, McCain has criticized Romney's economic record. The McCain campaign also has produced online commercials called "A Tale of Two Mitts" which criticize the former governor for reversing his position on abortion -- a right Romney previously supported, and now opposes.
Meanwhile former New York Mayor Rudy Giuliani, who staked much of his campaign on Florida, is in a close race for third with former Arkansas Governor Mike Huckabee, who won the Iowa caucus on January third.