It's a sunny Saturday in Cambier Park, the heart of Naples, on Florida's west coast, and local tea party activists are doing something unusual: They're holding a Thanksgiving food drive to benefit a local homeless shelter and food pantry.

The red-meat rhetoric is on hold. American flags abound amid swaying palm trees. "Gratitude not attitude," a sign says. That holiday spirit is what drew in Adam Sandy, who had never attended a tea party event before.

"I felt the tea party was too polarizing," says Mr. Sandy, who came with his tea partyer brother and a shopping bag full of food to donate. "It's good they're doing something positive."

Sandy is probably a rarity among the roughly 200 people here – an Obama voter in 2008. He says, even as a registered Republican, he could still vote to reelect President Obama next year. But for now, he likes libertarian Rep. Ron Paul (R) of Texas in the Florida Republican primary on Jan. 31. He supported Mr. Obama in 2008 because of his "message of unity" and his promise of economic solutions, but now he thinks "maybe we don't need government to create jobs."

And while Sandy is part of a cohort that leans Democratic – he's young (age 26) and college-educated – he's also unemployed and owes $30,000 in student loans. So he's just the kind of young voter the Republicans believe they can win next year on their way to retaking Florida, where unemployment remains high – 10.3 percent in October – and the home foreclosure rate is among the highest in the country. In 2008, Obama won Florida by fewer than three percentage points.

Welcome to the biggest, most diverse battleground state in presidential politics, where every demographic group and, lest we forget, every vote matters. It's been 11 years since the days of "hanging chads" and Bush versus Gore, when the Republican governor of Texas and the Democratic vice president came closer to an exact tie in the final deciding state than anyone dreamed possible.

In 2012, Florida will be a more valuable prize than ever. This time, 29 electoral votes are at stake, up from 25 in 2000, of the 270 needed for victory. For the Republican nominee, Florida is a must-win – thus the choice of Tampa for the GOP convention next August. For Obama, winning without Florida will be difficult but doable. He has electoral votes to burn from the 365 he won in '08.

For political junkies, Florida is a double paradise – a swing state in the general election and potential kingmaker with its early Republican primary. In 2008, Sunshine State Republicans dealt former Massachusetts Gov. Mitt Romney a mortal blow when they voted for Arizona Sen. John McCain, the eventual nominee, in their primary.

Nearly four years later, former House Speaker Newt Gingrich has burst forth into a commanding lead in polls of Florida Republicans – threatening to dash Mr. Romney's hopes once again. But talk to Florida tea partyers, who remain well organized around the state, and they're more animated by the prospect of defeating Obama than by coalescing around any one candidate.

"I'm for anybody but Obama – anybody who's for limited government," says Vinny Iannuzzi, who owns a pool maintenance company in Naples and is a tea party regular.

Tea party activists are famously unenthusiastic about Romney. But the latest general election numbers out of Florida from the Democratic polling firm Public Policy Polling (PPP) might give people like Mr. Iannuzzi pause. If the GOP nominates Mr. Gingrich, Obama would win Florida, 50 percent to 44 percent. If the party nominates the more moderate Romney, Obama would probably lose Florida, PPP suggests.

But with just a few weeks to go before the start of primary season, the GOP nomination race remains fluid. Neither party is assuming anything but a close outcome in the general election next November – and in Florida, critical voter groups are easy to spot: Hispanics, retirees, under-30s, suburban women, Jewish voters.

* * *

Luz Gaviria is one busy woman. She runs a Colombian restaurant – including waiting tables – that she and her husband own in the middle-class West Kendall neighborhood of Miami and has an 11-year-old daughter. After 18 years in the country, she's just become an American citizen.

"This is my first election," says Ms. Gaviria, a registered independent. When asked how she's leaning, she offers a soft endorsement of Obama: "He's good, but I haven't had a chance to check out the others."

Voters like Gaviria make the Democrats nervous. Even if she sticks with Obama, will she actually go to the polls? Hispanics are the fastest-growing minority in the nation, and the president needs to maximize their turnout to make up for declines in support from other groups, such as working-class whites. In 2008, Obama won two-thirds of the Hispanic vote nationwide and 57 percent in Florida.

In the lower-turnout 2010 midterms, Hispanics still voted Democratic nationally, but in Florida they went Republican, favoring Rick Scott for governor and the Cuban-American Marco Rubio for Senate. The difference: the state's substantial Cuban-American population, whose older community in particular tilts Republican and votes reliably.

In 2012, Florida's burgeoning Hispanic vote could decide the state, and the national party committees know it: They both started running Spanish-language TV ads last summer. But on the ground, the Democrats are a step ahead. The Obama campaign in Florida is already knocking on doors and running Spanish-language phone banks. In March, the Florida Democratic Party hired its first Hispanic outreach coordinator, Betsy Franceschini.

"In the past, we were always coming in at the last minute, four months before the election, trying to do things," says Ms. Franceschini, a longtime community leader in Orlando who is originally from Puerto Rico. "Now we're more proactive."

Franceschini has been working closely with Democratic activists around the state on mobilizing the Hispanic vote, organizing Hispanic caucuses, and getting the word out on changes to voter registration laws. In September, she helped set up a "White House Hispanic summit" in Orlando – the first to be held outside Washington. The event connected local Hispanics to White House officials on issues such as the economy, immigration reform, health care, and education.

In the media, Republicans called the summit a campaign "ploy." Franceschini called it "open to everybody" and a way to influence administration policy.

The choice of Orlando was no accident. The hometown of Mickey and Minnie has also become ground zero for Florida's Puerto Ricans, a population that has nearly doubled to 850,000 in the last 10 years. Unlike the Cuban-Americans, still the largest Hispanic subgroup in Florida at 1.2 million, the Puerto Ricans lean Democratic but are less of a sure thing on Election Day.

"The Puerto Ricans are very volatile in terms of voting," says Susan MacManus, a political scientist at the University of South Florida in Tampa. "A lot has to do with making a personal appeal, getting someone who can come in and speak Spanish and energize them."

The Republicans have in their hip pocket two powerful Spanish-speaking surrogates for their eventual nominee: former Gov. Jeb Bush and Senator Rubio. The Democrats don't have anyone analogous, thus the extra significance of the ground game.

Hispanics – namely, Cuban-Americans, who are centered in south Florida – are also influential in the GOP primary. Romney recently locked up the endorsements of three prominent Cuban-Americans: Rep. Ileana Ros Lehtinen; Rep. Mario Diaz Balart; and his brother, former Rep. Lincoln Diaz Balart. All three endorsed McCain in '08 and were critical to his victory over Romney.

Rubio has said he won't endorse in the primary. But he remains a special subject of fascination for the general election as a possible running mate for the Republican nominee. Rubio adamantly rules it out, but that doesn't stop the chatter.

Brad Coker, the Jacksonville, Fla.-based managing director of Mason-Dixon Polling & Research, sees Romney as the likely GOP nominee – despite the Gingrich surge – and if that happens, believes Romney will win Florida in November even without Rubio on the ticket. Mr. Coker takes Rubio at his word that he'll resist any effort to get him on the ticket. But if Rubio is asked and relents, Coker says, "he would be helpful in a lot of places, not just Florida."

At the Cafe Versailles in Miami, the social center of Little Havana, the Republican ticket – with or without Rubio – is sure to get the support of the old men who hang out by the takeout window and sip their Cuban coffee.

Manuel Coll, a retired truck driver and musician, reminisces about his arrival in the United States on July 2, 1960, and goes to his car to get his old Cuban passport, which he proudly shows his visitors.

When asked about Obama, Mr. Coll goes easy on him, as if he's a son who's in over his head. "He's not bad, but his suits are too big for him," Coll says. Who would be better? "Gingrich. He's prepared to be president." And how about the 40-year-old Rubio as his running mate? "Too young."

* * *

If the Cuban "old guard" is reliably Republican, the same can't be said about their children. Alejandro Miyar, a 30-year-old law student at the University of Miami and the son of Cuban immigrants, says he became a Democrat the day President Bill Clinton visited his middle school in Miami.

"I don't feel Marco Rubio and I have much in common," despite their common heritage, says Mr. Miyar, who worked for the Obama campaign in Florida in the last election.

Miyar also comes from the youngest swath of voters in the 2008 elections – the 18-to-29-year-olds, who backed Obama by the widest margin, a historic 34 points. Today, young voters are still the group most favorably disposed toward the president in national polls – 49 percent, according to the Pew Research Center – though their enthusiasm has waned substantially since Obama took office.

In Florida, the Millennial Generation is actually the least likely to approve of Obama's job performance, according to PPP. In a PPP poll released earlier this month, the 18-to-29-year-olds registered only 33 percent job approval for Obama, compared with 45 percent among all Florida voters.

But PPP also found that when given a choice, the youngest voters choose Obama over Romney by 10 points and Obama over Gingrich by 11 points.

"Florida's a particularly dramatic case of a phenomenon we're seeing nationally. Young voters aren't very thrilled with the job Obama's done, but they're still planning to vote for him over any of the Republican alternatives," says Tom Jensen of PPP.

At the recent Miami Book Fair, Sam Hayashi and Irina Tavera are eager to talk politics. Both recent college grads, they say they'll vote for Obama, though neither plans to volunteer.

"I was up in the air about Obama in the beginning; before the Republican debates, I was sure he would lose," says Ms. Tavera. But now, "the Republican candidates are pretty much destroying themselves from within. Obama's just sitting back and enjoying the show."

Mr. Hayashi thinks the Republicans' best option is Romney, but he can't see Obama losing. "I can't imagine a young person not voting for Obama," he says, though he acknowledges that by living in Miami, he's in a bit of a progressive bubble.

Polls show that Obama has plenty to worry about with young voters. A new group called Generation Opportunity is using social media to promote polling data that show plenty of room for Republican inroads with Millennials over the state of the economy, high federal debt and spending, and America's place in the world.

"In a very broad sense for 2012, that constituency is wide open and up for competition," says Paul Conway, president of Generation Opportunity.

And even if Florida is well known for its retirees, younger voters are growing in importance. People under 50 now make up 49 percent of the Florida electorate, compared with 45 percent just three years ago.

* * *

Ask Rod Smith, chairman of the state Democratic Party, about the big challenges Obama faces in Florida, and the answer is quick: turnout.

Will all those young voters who knocked on doors and rallied for Obama in 2008 volunteer again? Will they even make it to the polls? Ditto the non-Cuban Hispanics.

Another key voter bloc in Florida, senior citizens, can be counted on to cast ballots. But in this early going, the polling isn't promising for Obama. The recent PPP poll of Florida voters shows Obama underwater in his job approval rating among voters over 65, with 42 percent positive and 54 percent negative. And unlike young voters, who aren't happy with Obama's job performance but want to reelect him anyway, seniors are ready to vote Republican.

Romney's strongest favorability in Florida is with seniors – and among that group, he trounces Obama, 54 percent to 40 percent, according to PPP. Gingrich also does well among seniors, beating Obama 51 percent to 44 percent.

Some retirement communities, such as The Villages, north of Orlando, are GOP strongholds. But Obama can't even feel completely secure among Florida's older Jewish voters, a mainstay of the Democratic coalition. Jeannie Hochhauser and her friend Seymour Wilens, both of Sunrise, Fla., are solid Obama supporters, but mention Israel, and they raise concerns.

"I don't like the fact that he's catering to the Arabs," says Ms. Hochhauser, a schoolteacher from Brooklyn, N.Y., who retired to Florida 26 years ago. "It bothers me. But it bothers me more that seniors are hurting and people are having to walk away from their homes." So, she says, she's for Obama, but "he could be a little more emphatic."

Mr. Wilens, who retired here from New Jersey, is active in the Sunrise Democratic Club. On a recent visit to the club, his congresswoman, Rep. Debbie Wasserman Schultz (D), spoke of Obama's support for Israel and handed out fliers about Obama and Israel.

"There's quite a bit of doubt," says Wilens.

Still, Obama has no better advocate among Florida's politically active Jewish community than Representative Wasserman Schultz, who also chairs the Democratic National Committee.

"Debbie's the sweetest thing," says Hochhauser.

* * *

The joke in Florida is that instead of having the whole state vote for president, it would be a lot easier just to ask a moderate suburban white woman under age 50 from the Tampa Bay area – the ultimate swing demographic in the state's ultimate swing region – to choose.

So we found one. In 2008, April Smith was an enthusiastic Obama supporter who donated money and put an Obama sign on her car window. But she's been disappointed in his performance, and her vote is up for grabs. She's tired of all the Obama fundraising e-mails flooding her in-box, and wishes the president would explain better what he's done and what he would do with a second term. She has removed the Obama sign.

"The fact that he didn't have a plan to address unemployment until recently was very upsetting to me," says Ms. Smith, a graphic designer and a transplant to the area, like many in Tampa. "Maybe someone with Romney's business experience actually has some ideas."

Smith also mentions Americans Elect, a nonpartisan online effort to select a presidential candidate who transcends party politics. She plans to take part.

What if Obama replaced Vice President Biden on the Democratic ticket with Secretary of State Hillary Rodham Clinton?

The idea has been the subject of pundit chatter in recent months. The theory is that Secretary Clinton could help Obama with moderate women voters in key swing states like Florida, Ohio, and Pennsylvania – all states that Clinton won handily in the 2008 Democratic primaries.

"If she was on the ticket, I would definitely feel better about reelecting him," says Smith. "I've not seen anything from Biden. He seems like a cardboard cutout."

Smith's assessment of Obama captures the mood of many one-time supporters – a feeling of being let down after such high expectations. But Republicans are worried that once the general election campaign begins in earnest, his personal popularity will change the equation.

"That's going to be our challenge," says Leonard Curry, Florida's new Republican Party chairman. "We have to recognize that people like Obama as a person, but just because you like someone doesn't mean they should be president."