Des Moines - After a year of campaigning and a blizzard of negative ads, Iowa voters will finally decide Monday whether to back the anti-establishment candidates who have made this wild presidential election so unpredictable or stick with more mainstream contenders.

The outcome will answer whether the surge of enthusiasm that has rocketed insurgent candidates to the top of the Iowa polls can translate into votes in a low-turnout caucus that thrives on the nitty-gritty minutiae of getting Iowans to the caucus.

Can Donald Trump pass his first test? The Republican political newcomer wants to prove the boisterous rallies that attract thousands of supporters can actually translate to votes, and Monday's vote in frigid Iowa will be his first chance to test how deep his support runs. Polls show he holds a steady, if slim, lead over Texas Sen. Ted Cruz, and his supporters believe he can sweep the four contests in the early-voting states if he can win in Iowa. That's a very big if.

Will first time voters show up for Bernie Sanders? Much like Barack Obama in 2008, Vermont Sen. Bernie Sanders depends on young, more liberal voters to caucus for him tonight to defeat frontrunner Hillary Clinton. He's attracted huge crowds of mostly younger voters at rallies around the state with folks eager to send a message that they will muster on Monday. "We will caucus," they chanted over and over again at a Sunday event in Des Moines. They will have to if he wants to derail Clinton's campaign.

Can Ted Cruz flip the script?  The Texas senator is, in many ways, perfect for the Iowa electorate. He's evangelical, deeply conservative and popular with the tea party movement. Yet he's slipped in the polls as Trump and Florida Sen. Marco Rubio have gained traction, and his uneven performance in last week's debate in Des Moines triggered new attacks from GOP opponents who painted him as a political opportunist. If he loses Monday, his "conservative track" strategy takes an enormous hit.

Will Marco Rubio emerge as the establishment favorite? Rubio has long tried to position himself as the mainstream alternative to Trump and Cruz, but he's been unable to consolidate support from the party's establishment wing. Polls show him in a solid third place behind the two top Republicans, but he's faced withering attacks from former Florida Gov. Jeb Bush and other rivals. Monday's vote could help cement his position - or bare his weaknesses.

Who will drop out? The Iowa vote will start the culling of the candidates, although many of the also-rans may wait until later in the month to quit the race. Trump's announcement of a rally in Little Rock on Wednesday has already stoked speculation that former Arkansas Gov. Mike Huckabee could endorse him, and ex-Pennsylvania Sen. Rick Santorum will also face tremendous pressure to bow out if he does poorly.

How will the weather affect the caucus? A snowstorm homing in on Iowa is expected to dump as much as a foot of snow across western Iowa, and some forecasts have the first wave covering the rural - and deeply conservative - counties bordering Nebraska as caucuses open. That could hurt the Cruz campaign, which has crisscrossed the region for months.

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