After eight months of campaigning, 13 debates, and "$13 million in mostly vicious and anonymous TV attack ads," Iowans are finally casting the first ballots of the 2012 presidential election on Tuesday night, says Michael Scherer at TIME. And as "absurd" as it seems that "the world's richest, most advanced democracy has randomly endowed a few thousand residents of a state known mainly for corn, hogs, and gas stations called Kum & Go with the responsibility of first screening its prospective leaders," the political world is watching Iowa with bated breath. "Unpredictable to the end," Iowa Republicans are split into a tenuous three-way tie between Mitt Romney, Ron Paul, and Rick Santorum, with the biggest share of voters still uncommitted, say the AP's Kasie Hunt and Philip Elliott. Here, seven key things to look for as Hawkeye State Republicans line up to caucus:

1. What is Mitt Romney's ceiling?
"The most important question of the evening," says Maggie Haberman at Politico, is: "How high can Mitt go?" Romney has predicted that he can win, and the polls back him up. But if he "can't climb higher than the mid-20s — like Bob Dole in 1996 — it will keep alive the lingering questions about whether he can win over the leery Republican base." Republican insiders put Romney's magic number at 28 percent — higher than that, and he'll have claimed a true victory. But regardless of his share of the vote, if Romney comes in lower than a close second place, the results will certainly "be tough to spin."

2. Will young voters save Ron Paul?
In 2008, voters under 30 "turned out in droves to help deliver a stunning victory for Barack Obama in Iowa," says Katy Steinmetz at TIME. This time around, Paul is banking on a similar "youth revolt." It's not implausible: He may be in his 70s, but "there is an air of rock 'n' roll around Paul," and young voters like his anti-war views, vow to legalize drugs, and relatively moderate views on gay marriage. But most colleges are still on Christmas break, and even though he's polling well with Democrats and independent voters, the Texan's success Tuesday rests on the questionable assumption that "Paul will get the kind of volunteer brigade Obama did."

3. Will evangelicals deliver for Rick Santorum?
Four years ago, nearly 60 percent of caucusgoers identified themselves as evangelical Christians. "It will be interesting to see that number tonight," says Michael Shear at The New York Times. "If it is high, that would likely help Rick Santorum," who is aiming for the same coalition of evangelicals, home-schooling activists, and other social conservatives who propelled Mike Huckabee to victory in 2008. But if the number is low, it suggests "that the really motivated voters this time around are the ones fired up by economic concerns, not social ones," which would probably help Romney.

4. Who will come in fourth?
"Typically, there are only three tickets out of Iowa," says Politico's Haberman, but this year might be different. With expectations so low, "a closer-than-expected fourth-place finish could be spun into something a bit better." Especially if the "fourth place Iowa finisher" is Newt Gingrich or Rick Perry, says The New York Times' Shear. With Paul widely viewed as unelectable and Santorum's shoestring campaign too weak to compete against Romney, either Perry or Gingrich could "emerge as the most effective voice inside the party arguing against a coronation" of Romney.

5. Who will spin the results most effectively?
"The Iowa caucuses are a two-step process: First comes the voting, then comes the spinning," says Nate Silver at The New York Times. And the spin might be more important than how a candidate places: A surprise second-place finish, for example, can "produce a bigger impact than finishing first." This year, "by far the most consequential outcome in Iowa would be if Mr. Romney performed much worse than expectations," perhaps winning just 15 percent. That same percentage could be spun as a win for Santorum, though. And thanks to "the perversity of the expectations game, by failing to achieve expectations in one state, a candidate may lower them in another."

6. How many Republicans will turn out?
"One of the greatest unknowns today is turnout, something that can't be easily predicted by polls," says John McCormick at Bloomberg. About 120,000 Republicans turned out to caucus in 2008, and this year's "level of participation will be a peek into the crystal ball of partisan enthusiasm in a swing state that will be crucial to both sides in the general election," says Shear at The New York Times. "If 140,000 or 150,000 voters show up to the caucuses, that would be a good sign for Republicans." Anything lower would signal that the 2010 "tidal wave of Republican energy" has ebbed. 

7. What will the weather be like?
With Republicans unenthusiastic about a GOP presidential "field that's widely been panned as weak, turnout may depend on something as mundane as the weather, says Politico's Maggie Haberman. If it's frigid or wet, "the wide perception is that it will favor Paul, whose supporters are generally seen as more motivated than anyone else." If it's just "cold but dry (and manageable)," older voters are more likely to join the caucuses, which may be good news for Romney.