WEST PALM BEACH, Fla. — Sen. John McCain is not a true Republican and he does not understand the economy while Mitt Romney is a "flip-flopper" who cannot keep his facts straight.

Welcome to the world of dueling campaign rhetoric in the midst of today's tightly contested winner-take-all Florida Republican primary.

Voters hit the polls today to eventually award 57 Republican delegates as well as a first-place finish that could give the winner a boost the week before Super Duper Tuesday on Feb. 5. More than 20 states, including Utah, hold primary elections or caucuses for one or both major political parties that day.

It got ugly on the campaign trail Monday as Romney and McCain upped the rhetoric and their attacks on each other.

Romney used a sunrise press conference at a Texaco station in West Palm Beach as the backdrop for his continued criticism of McCain. His go-to example was the McCain-Lieberman climate change bill, which Romney says will increase gas and electricity prices to the tune of $1,000 per year for a Florida family of four.

"What's particularly troubling about the bill is that the effect on the global environment would be negligible," Romney said. "The bill does not require other nations to participate."

Romney said that missing requirement would merely force high-emitting industries to leave the United States to go to countries with lower requirements — taking their jobs with them.

"As someone who has spent his life in business, I know how business people think, and they will follow the course of least resistance," Romney said. "If we put a huge burden on our industries and homeowners, the industries will move to places where those burdens don't exist."

Romney pounded home his point at airport hangar stops across the state — that McCain-Lieberman and two other McCain-sponsored bills illustrate how he is the wrong choice for Florida and the nation.

"If somebody wants to know where he would lead the country they simply need to look at the three pieces of legislation with his name at the top," Romney said.

He told crowds that the McCain-Feingold law on campaign finance "has not reduced the influence of money and politics, it's made it worse." And he lambasted the McCain-Kennedy proposal on immigration as an "amnesty bill."

Romney said, "All three are bills evidence a lack of understanding of our economy, the very lack of understanding that Sen. McCain has admitted on numerous occasions."

McCain's campaign, also on the final-day stump, shot back quickly with a statement.