New Hampshire, it's your moment. Voters in the first-in-the nation primary are getting the chance to cast judgment on the presidential field in a vote sure to shake the race to the White House.
Here are five things to watch in the Granite State on Tuesday:
1. Trump's biggest test
Real estate mogul Donald Trump faces the same question he did before last week's Iowa caucuses, where he finished second despite often leading in the polls: Can he turn big crowds and media buzz into votes?
The billionaire businessman got something of a pass last week, since the evangelical and social conservative voters that are disproportionately important in the Hawkeye State were more natural backers of Texas Sen. Ted Cruz.
But if his vote share in New Hampshire significantly dips below his polling number of 31 percent, as calculated by the latest CNN/WMUR tracking poll, it will raise serious questions about the ceiling for his political support and his capacity to widen his appeal later in the race.
Even Trump admitted he had failed to put together the kind of ground game needed to win in Iowa. And despite a late flurry of campaigning in the days leading up to the primary, he has also mostly steered clear of retail campaigning and data-driven voter targeting that are considered key in New Hampshire. So no one -- least of all the Trump campaign -- knows how many of the billionaire's passionate, anti-establishment supporters are going to turn out.
While he tried to repackage his second place showing in Iowa as a victory, Trump understands that New Hampshire, where he has led every single public poll since June, holds much greater significance for his presidential hopes.
"I could say to you if I came in second and third I'd be thrilled, OK? I know all about expectations," Trump told CNN's Dana Bash on Sunday. "If I came in second, I wouldn't be happy, OK?"
2. Rubio: Rebound or out?
New Jersey Gov. Chris Christie's roasting of Florida Sen. Marco Rubio at the GOP's Saturday night debate has reverberated on the campaign trail and dominated political news coverage ever since.
But we won't know for sure if it damaged the first-term senator from Florida until votes start rolling in Tuesday night.
Rubio had arrived in New Hampshire on a high after a strong showing in Iowa and seemed set to win the battle for second place -- a result that would allow him to argue that he is the only establishment candidate able to fight Trump and Cruz, who beat him in the caucuses.
But if Rubio's shaky performance Saturday led undecided Republicans to question whether the 44-year-old first-term senator is ready to be president, it could hand a lifeline to former Florida Gov. Jeb Bush, Ohio Gov. John Kasich and even Christie himself.
That could mean that the filleting of the establishment bloc after New Hampshire could be less savage than expected and hand some or all of that trio a ticket to later contests.
That would be good news for the outsider crew as a still-fractured establishment field can only help Trump and Cruz heading into South Carolina and the sweep of big-state primaries on March 1.
Alternatively, it's possible that Rubio's repetitive mantra at the debate -- so mocked by Christie -- that President Barack Obama is on a mission to dismantle everything that made America great may have resonated with conservative voters in a mood to defy the Washington pundits and the media.
If that's the case, Rubio could rebound from Christie's pounding to enjoy a bigger-than-expected Granite State boost.
3. How hot is the Bern?
It's not whether Sanders wins. It's about by how much. At least, that's what a reading of the polls seems to indicate.
Surveys suggest he is such a prohibitive favorite in New Hampshire that a Clinton come-from-behind victory would rank as one of the biggest upsets in the Live Free or Die state's political lore.
The CNN/WMUR tracking poll on Monday had Sanders leading the race by 26 points. If the gap turns out to be that wide in a state Clinton won in 2008 and which made her husband Bill Clinton the Comeback Kid with an expectations-defying second-place finish in 1992, the simmering rumors about a shake-up in her campaign will boil over. While Clinton's firewall in the next primary state in South Carolina might be intact, Sanders would send a message that he can compete in northern, delegate-rich states to come such as Ohio, Pennsylvania and Michigan.
A huge Sanders victory would also set off a new avalanche of fundraising for the Vermont senator -- and it would suggest that his assaults on Clinton, whom he is painting as an inauthentic progressive and abettor of Wall Street greed, are beginning to have a serious impact on her image among Democrats.
Both campaigns will be closely watching exit polls for evidence that Clinton's hold on women -- once thought unshakeable owing to the historic possibility that she could be the first female president -- could be further slipping.
While Clinton led Sanders among married women in Iowa, he outpaced her by a distance with unmarried, younger women, who are less prone to see her as a feminist icon.
But if the former secretary of state could keep the deficit in single figures, her campaign will be able to spin a line that she performed better than expected in a state where Sanders, a longtime resident of neighboring Vermont, had built-in advantages.
That would send her off to looming contests in South Carolina and Nevada with a spring in her step to court more diverse electorates where African American and Hispanic votes are key and where Sanders is at a disadvantage.
4. Who stars at the governor's ball?
If nothing else, this election may rewrite the conventional wisdom that running a state offers a leg up to the White House.
That's because it's been a grim year for the Governor's Club, with four of the members who entered the race -- Republicans Rick Perry, Bobby Jindal, Scott Walker and Democrat Martin O'Malley -- crashing out early.
But three governors are still standing.
And if Rubio performs more poorly than expected, there may well be a spot for at least Kasich, Bush or Christie to continue on in a race dominated by grass-roots fury against the establishment and in which a paucity of governing experience is a vote winner, not a disqualification.
The sleeper favorite may be Kasich, who has been less ready to throw negative punches than Christie and Bush and thinks he could spring a surprise with a strong finish in the New Hampshire primary.
Bush, meanwhile, is desperate to avoid the humiliation of being forced out of the race in a state that he once saw as his best chance for an early victory. He must do well enough to stay alive and to at least consider whether it makes sense to move on to South Carolina, which rescued his brother George W. Bush's campaign in 2000.
Christie, with just 4 percent of the vote in the latest CNN/WMUR tracking poll, will be hoping that his assault on Rubio will inject a last-minute boost to his campaign.
5. The fallout
It would be a surprise if the New Hampshire primary does not mean the end of the road for some candidates.
After all, four of them -- Republicans Mike Huckabee, Rand Paul and Rick Santorum and Democrat Martin O'Malley -- pulled out after failing to feature in Iowa.
It's certainly possible that lower-place finishers could decide to call it quits after New Hampshire, especially those who had seen the state as their best early voting hope.
One candidate who has already booked his spot in later rounds is Cruz, thanks to his victory in Iowa.
But the Texas senator's vote total will be worth watching. If, for instance, he were to defy expectations in New Hampshire, which is more secular and moderate than Iowa, his candidacy could still get a boost from the Granite State.