The Hawkeye State accounts for a mere 28 of the almost 2,300 delegates who will anoint a Republican presidential candidate at the national convention in August. Yet the 100,000 or so Iowans expected to turn out for Tuesday's GOP caucuses could make or break the candidacies of several of those vying for the nomination.
Talk about a power trip.
The direction the Republican race takes after Iowa is directly influenced not only by who wins the caucuses, but by who does not. How the candidates place will determine who has the momentum heading into the New Hampshire and South Carolina primaries later this month.
Here's what to look for on Tuesday night.
Is the Santorum surge for real?
Rick Santorum, who lost his Pennsylvania Senate seat in 2006, was never supposed to be a contender. But without the money or staff for a national campaign, he was forced to spend nearly all of 2011 in Iowa, plying voters in every hamlet.
It is now paying off. Evangelical Christians made up more than half of Republican caucus-goers in 2008, when former Arkansas governor Mike Huckabee ran away with Iowa. If they turn out in numbers that great on Tuesday, Mr. Santorum could be the surprise winner.
Fiercely anti-abortion and anti-gay marriage, he is the only candidate to experience a last minute surge in the polls. That may reflect a desire among social conservatives, who have split their support among several candidates until now, to unite behind a single contender.
Mr. Santorum has two major shortcomings going into the vote, however. First, he is no Mr. Huckabee, whose warmth and good humour made him instantly likeable.
Besides, his re-election loss remains a reflection of just how much he alienates mainstream voters.
Still, he has become a better politician since his senate defeat. He showed that on Sunday's Meet the Press, with this clever comeback: "Who goes from losing their last Senate race to winning the presidential nomination? The answer to that was Abraham Lincoln."
Can Romney hold on?
Mitt Romney has spent the entire campaign playing down expectations for Iowa, where his 2008 bid for the nomination met its Waterloo. But with polls now showing the ex-Massachusetts governor in first place in the state, he must perform extremely well on Tuesday or face growing concerns that anti-Romney sentiment in the party is too strong for him to overcome. That would damage his chances in South Carolina and Florida and possibly resuscitate the candidacies of Newt Gingrich and Rick Perry.
The consensus viewpoint is that Mr. Romney does not need to win Iowa. But he must place at least a strong second or be among a cluster of candidates at the top.
The on-the-ground evidence suggests he will pass that test with flying colours, as he draws the biggest crowds and possesses the most sophisticated organization.
But with at least 40 per cent of likely caucus goers saying they could change their minds by Tuesday, Mr. Romney will need to rely on recruiting supporters to twist the arms of fellow voters when Iowans caucus in almost 1,800 precincts on Tuesday night.
Will independents choose Paul?
Democrats are also caucusing on Tuesday night. But with President Barack Obama not facing a challenger, it frees up thousands of independent voters to participate in the Republican caucuses this year. Voters can change their party registration right up until the last minute in order to join in the GOP discussion.
Indeed, libertarian candidate Ron Paul is counting on thousands of unaffiliated voters, especially college students, to propel him to the top.
A week ago, it looked like the Texas congressman might just get his wish. But he has been losing momentum in recent days as he faces attacks from the other candidates about his isolationist foreign policy and electability in a national race.
Will Iowa be the end of the road for Perry and Gingrich?
Texas Governor Rick Perry and former House of Representatives speaker Newt Gingrich both need to exceed expectations in Iowa to have much hope of mounting a comeback and beating Mr. Romney.
For Mr. Perry, a failure to rally more than 10 per cent of caucus-goers would likely spell the end. A score of 15 per cent or more would signal that enough Republicans are willing to give him a second look as the search for an anti-Romney continues.
Mr. Perry, who raised nearly as much money as Mr. Romney while he led the field last summer, has the war chest to carry on. Iowa will determine whether he has the support.
Mr. Perry has made an open play for Iowa's evangelicals in recent days, changing his stand on abortion to oppose the procedure even in cases of rape and incest and switching his campaign slogan to "Faith, Jobs, Freedom" from "Get America Working Again."
As for Mr. Gingrich, he has been in such a freefall in recent days that any result below 15 per cent would make it hard for him to become a contender again – though he has insisted he is staking everything on a win in South Carolina.
Will Michele Bachmann call it quits?
The Minnesota congresswoman has lurched from one gaffe to another since winning last summer's Ames Straw Poll, an early test of strength in Iowa.
She blew her comeback chances in September, when after deftly skewering Mr. Perry over his Big Brother-like effort to force adolescent girls in Texas to get the HPV vaccine, she went on to suggest a link between the shot and "mental retardation."
She wasted her last days in Iowa accusing her former state campaign chairman, who jumped ship to Mr. Paul, of making the switch for money. She has gone through staff like paper towels, raising questions about her temperament.
She is, however, stubborn. As long as she remains in the race, she will able to count on a core of die-hard supporters. That, too, would help Mr. Romney in the long run.