(CNN) -- From outward appearances Tuesday's special election to fill a vacant congressional seat in Florida doesn't seem to be that important. It's just one of 435 seats in the U.S. House, and the winner will serve out a term that comes to a close at the end of the year.
But the contest for Florida 13 has landed smack in the middle of the national political spotlight. It's seen by some pundits as a bellwether for November's midterm elections, and there's been a massive infusion of outside ad money into the race to try to influence the outcome.
A special election this far out from Election Day rarely gives us a preview of what will actually happen in November, but the party that does come out on top gets bragging rights until the next election.
Democrat Alex Sink is running against Republican David Jolly to fill out the term of Republican Bill Young, who died in October. Young, first elected to Congress in 1970, was the longest-serving Republican in the House.
Sink was Florida's chief financial officer and narrowly lost the 2010 gubernatorial election to Rick Scott. Jolly served as a former general counsel for Young and also worked as a lobbyist. There's also a libertarian candidate in the race.
Here are five things we can learn from the race:
1. Swing district in a swing state: The district covers most of Pinellas County and parts of St. Petersburg near Tampa, and it's up for grabs. While Young captured 58% of the vote in his 2012 re-election, President Barack Obama narrowly carried the district. Obama also won it in 2008, grabbing 51% of the vote. It went for George W. Bush before that.
Of those registered to vote in the district, 37% are Republicans, about 35% are Democrats and 28% are unaffiliated. Public opinion polls suggest the race remains close. With the number of competitive House seats shrinking with every cycle, Florida 13 is becoming something of a rarity.
While both parties have a lot at stake, and both have tried to lower expectations, a top nonpartisan political handicapper says the Democrats have more to lose.
"It's rare in politics that anything other than a presidential contest is viewed as a must-win, but the special election in Florida's 13th District falls into that category for Democrats," wrote Stuart Rothenberg, editor of the nonpartisan Rothenberg Political Report.
Rothenberg points out that all things being equal, Sink should win, since she didn't have a primary challenge and had a money advantage, and Jolly had to continuously battle the lobbyist label.
"Since most nonpartisan handicappers and analysts have for years expected this seat to go Democratic when it became open, a Republican victory would likely say something about the national political environment and the inclination of district voters to send a message of dissatisfaction about the President. And that possibility should worry the White House," Rothenberg said.
2. Is it all about Obamacare?: National Republicans are framing the election as a referendum on Obamacare. The National Republican Congressional Committee and pro-GOP outside groups link Sink to the health care law, to President Obama and to House Democratic Leader Nancy Pelosi.
"Canceled health plans. Higher premiums. Medicare cuts. People losing their doctors. A disaster for families and seniors. For Alex Sink the priority is Obamacare. Not us," says the narrator in a TV commercial by the Chamber of Commerce, which is backing Jolly.
That's a potent message in a district that's one of the grayest in the nation. Nearly a quarter of all residents in Florida 13 are 65 or older.
Jolly says he remains committed to getting rid of Obamacare entirely.
Sink recognizes that Obamacare is a major issue. While she highlights how the Affordable Care Act has helped people, she also notes that the law has flaws, and says she's open to GOP proposals to amend some of the measure's requirements.
"Regardless of whether or not the election will tell us anything about November, the two political parties will learn lessons from this contest and apply them to future races," Rothenberg said. "If Jolly wins, it's all about Obamacare for the GOP. And if Sink wins, Democrats will say that attacking Republican candidates on Medicare and Social Security works."
3. Excitement could translate to turnout: While special elections typically see far lower turnout than general elections, the race in Florida could have a strong showing -- a statistic both sides will be eagerly trying to gauge to predict turnout in November.
Early voting turnout is already higher than the total turnout for the last special election in Florida, when Democrat Ted Deutch won in 2010 after Democrat Robert Wexler resigned.
Nancy Whitlock, a spokeswoman for Pinellas County elections, said about 27% of eligible voters in the district have already voted by mail or in person.
By contrast, turnout for that 2010 special election was about 15% of eligible voters. That's the total figure, not just early voting.
While registered Republicans outnumber registered Democrats in the 13th District by about 11,350 voters, Democrats seem to be excited about the high early voting turnout so far.
"These are tests of turnout to some extent," Rothenberg said. "Democrats are already talking about how they are doing better in the early voting than they thought they would."
4. Most expensive race so far: The contest has seen an outsized level of third-party spending, making it the most expensive race this election cycle, even more than last year's Senate special election in Massachusetts to replace former Sen. John Kerry.
Outside spending also tops the current Senate race in Kentucky, where Senate Minority Leader Mitch McConnell is defending his seat.
In addition to the $2.4 million spent by the campaigns themselves, as of mid-February nearly $9 million had been spent by outside groups, according to the Center for Responsive Politics, which monitors outside spending.
Sheila Krumholz, executive director of the CRP, said the influx of cash has to do with the start of the 2014 midterms.
"It seems like an anomaly that there would be all this outside interest when it's going to have to be fought again in November," she said. But she added that groups are interested in this race in part because there's "no other show in town yet."
Outside money, she said, can significantly strengthen or weaken the eventual victor when the race plays out again in November, but it also plays a large role in determining the dialogue and themes in the contest.
Breaking the numbers down, Jolly appears to have an advantage in third-party spending.
About $623,000 has been spent in efforts to oppose Sink, and Jolly has benefited from about $600,000 more to support him than his opponent.
American Crossroads, the conservative super-PAC backed by Karl Rove, and the U.S. Chamber of Commerce are two of the largest super-PACs that have backed Jolly. On the Democratic side, House Majority PAC put in nearly $1 million.
The two campaign arms in the House dished out the most cash in the race -- the National Republican Congressional Committee slightly outspent the Democratic Congressional Campaign Committee, $2.2 million to $2.1 million.
5. From Barker to Biden to Bowzer to Bubba: Beside the national money and attention, the race also landed some big-time surrogates. Vice President Joe Biden flew in to headline a fundraiser for Sink, and former President Bill Clinton recorded an automated call for the Democratic candidate.
Sen. Rand Paul of Kentucky, a rock star among grassroots conservatives, recorded a robocall for Jolly, and former Florida Gov. Jeb Bush starred in pro-Jolly TV commercial.
But it wasn't just politicians.
Bob Barker, the longtime host of "Price is Right," starred in an ad for Jolly in December. And in another blast from the past, Jon "Bowzer" Bauman from Sha-Na-Na fame campaigned for Sink.