Charlie Black, a senior adviser to McCain, acknowledged Monday that Romney has been able to spend a lot more money in the state than the senator. But Black said McCain’s early wins and endorsements have allowed him to “catch” Romney in the Sunshine State.

Black said McCain and Romney are going down to the wire, but without Romney’s paid staff and “millions of dollars on TV, it wouldn’t be close.”

Romney has clearly spent far more time advertising on television than has McCain. The Nielsen Company — which tracks media campaigns — said on Monday that since March 2007, Romney has run 4,475 ads in the state. By comparison, former New York City Mayor Rudy Giuliani has run 3,067 and McCain has run just 470.

While Romney has had staff on the ground for more than a year, McCain’s operation — which is largely driven by volunteers — only returned to the state in the last two weeks, one Republican strategist said, giving Romney a “definite advantage.”

Both of the campaigns have volunteers working the phones feverishly as they try to turn out votes.

“Everybody’s scrambling to turn out their favorable voters,” Black said.

Some of those voters, however, have already made their preference known. Florida allows for early voting, and state officials said over the weekend that more than 400,000 Republican voters have taken advantage.

Turnout might take care of itself, though, as Florida voters will also be going to the polls to vote on a property tax ballot initiative, a factor state officials think will drive Republican turnout.

Sources in the state say Giuliani will likely do well with the early voters, as he has had the state to himself over the last month while ballots were cast and his rivals were battling in the earlier-voting states.

An aide to Giuliani downplayed the notion that Romney has a superior ground operation, and the former mayor has said repeatedly in recent days that he will win Florida.

For a campaign that now appears to be based almost entirely on a win there, failure to do so would appear “to be a monumental strategic error,” Dinerstein said.