As the Republican presidential nominating contest moves to Florida, it’s important to remember one simple fact: Florida is a very different political animal than the three states that have preceded it.

Iowa, New Hampshire and South Carolina are all small-ish states with largely homogenous — white — Republican primary electorates. Retail politics is the name of the game. And momentum can swamp organization and money.

Florida is a massive state — 1.9 million Republicans voted in the state’s 2008 primary, double the amount that have cast ballots in Iowa, New Hampshire and South Carolina combined this year — with a diverse population. (Savvy GOP political analysts estimate that 10 percent of the votes cast in the Jan. 31 primary will be from Latinos — Cubans, to be specific — largely clustered in south Florida.)

Organization is a must in Florida. Unlike the three states that have voted already, Florida has a robust absentee and early voting program. One unaligned Republican strategist who has worked extensively in Florida estimates that as many as 500,000 votes will be cast by absentee ballot, half of which have already been mailed in. “So a half-million votes were basically ‘out there’ before Saturday night,” the strategist said. “This is definitely good news for Mitt. He has been working the absentee ballots with mail and phones.”

And from the day of the South Carolina primary through Saturday, Florida voters can — and will — vote at local polling places. That makes winning every day’s national media story — as former House speaker Newt Gingrich very clearly did on the first day of early voting in Florida — absolutely critical. The breadth of early voting across Florida makes every day between now and Saturday a mini-primary day.

Perhaps the biggest difference, though, between Florida and the states that have voted before it is the importance of television advertising to communicate with voters. The state is covered by 10 media markets, and a statewide television buy of genuine significance will run into seven figures for a single week.

And when Florida political types talk about a candidate’s winning math in the Sunshine State, they talk about it by media market. That conversations begins — and virtually ends — with the “I-4 corridor,” a highway that runs across the central part of the state, connecting Orlando on the northeastern side to Tampa on its southwestern end.

At least half — yes, half! — of the Republican primary vote will come from the Orlando and Tampa media markets, making winning the I-4 corridor tantamount to winning the state. In the 2008 Republican presidential primary, Arizona Sen. John McCain won the four main I-4 corridor counties — Orange, Osceola, Polk and Hillsborough — with between 33 and 37 percent of the vote; he won statewide with 34 percent.

The other media markets to keep an eye on are Jacksonville and Miami, with each likely to provide roughly 10 percent of the primary electorate.

Turnout, by the way, remains something of an open question. The 1.9 million number in 2008 was fueled not only by a very competitive and costly fight between McCain and former Massachusetts governor Mitt Romney but also a property tax reduction amendment — known as Amendment 1 — that brought out voters with little to no history of participating in past Republican primaries. (It passed with 64 percent of the vote.) By way of comparison, just under 1.3 million Republicans voted in the 2010 gubernatorial primary between Rick Scott and Bill McCollum.

The closer the size of the electorate is to 2010 rather than 2008, the better for Gingrich. A smaller turnout means more reliable (and conservative) Republicans have more say in picking the winner, and that’s how Gingrich bested Romney in South Carolina.

And speaking of political ideology, Florida’s is best understood, according to longtime Sunshine State politicos, through a geographic prism. The state starts off conservative — fiscally and socially — in its northern reaches (think the Panhandle) and moves toward more straight fiscal conservatism through its central region (I-4 corridor) and to something close to centrist moderation in the south (Miami).

Expect Gingrich to clean up in northern Florida, Romney to win the southern part of the state and for the central part to be where the fight is decided. Just like always.