Finally. Election Day. It's almost here.
The campaign that many thought would never end is ending tomorrow. Here's our handy guide to some things that the results will tell us — and why they matter for the future.
1. What message do American voters want to send with their choice for president?
Yes, the presidential race is very close, and some public polls show it getting closer as we go into the final hours, but in one sense it's actually been stable for months.
Hillary Clinton has had a small but persistent lead since June — anywhere from 2 to 5 points. The stock markets and the election betting pools are predicting a Clinton win. So, if Donald Trump wins, it will be a seismic event.
He would make history in so many ways because he is a candidate who eschewed the traditional arts of political campaigns, including field organization, traditional advertising, debate preparation and policy knowledge. Plus, he's a candidate who divided his own party more deeply than any presidential candidate has before.
Republican voters are coalescing behind Trump, but many Republican elected officials still say they can't support him.
If Clinton wins, history will also be made: She would be the first female U.S. president, of course, but also the only candidate in the modern era, other than George H.W. Bush, who managed to follow a two-term president of her own party.
2. How big is the victory?
The winner's margin of victory also matters. If it's a squeaker, that will make the lessons learned for both parties much murkier.
A big win for Clinton would allow her to claim that the country rejected Trumpism, while a narrow win leaves her limping into office with the highest unfavorable ratings for any new president.
If Trump wins narrowly, Democrats can blame the loss on FBI director James Comey, who inserted himself late in the campaign in an unprecedented way. If Trump loses narrowly, it will make it much harder for the GOP to unify. Under that scenario, the Trumpists are likely to argue that the election was lost because the Republican establishment failed to rally around the choice their own voters made.
3. What does Trump (or Clinton) do after the votes are counted?
Trump has said he will accept the results of the election — if he wins. And he has said the only way he can lose the election is if it's stolen from him. Weeks before any votes were cast, he was predicting widespread voter fraud. So if he loses, what does he do?
Does he accept the results and concede graciously, pursue legal action, or tell his followers to take to the streets? Even if Trump concedes, some of his supporters have promised to take up arms against Clinton. Will he encourage them? What if he says he plans to run again in 2020?
And what does Clinton do if she loses? Concede? Blame the Russians? Or the FBI? The aftermath of this extraordinary election could be just as surprising as the race itself.
4. How did the electorate change?
Trump's path to victory depends on getting historic levels of support from white voters, and particularly large numbers of white, non-college-educated voters. Mitt Romney got 59 percent of the white vote in 2012, considered by many to be a high-water mark with this demographic group. Can Trump win a higher share of white voters than Romney and get more of them to turn out?
White voters were 72 percent of the electorate in 2012, and their share of the population has shrunk a couple points since then. Trump has had trouble winning certain segments of the white vote, such as suburban women and college-educated voters.
Republican candidates have won whites with college degrees in every presidential election since polling began. This year, however, polls show Clinton winning white college-educated voters by double digits.
But Clinton has also struggled with key groups of voters. Tuesday's results will show if she was able to reassemble the Obama coalition of young people, Hispanics and African-Americans.
African-American voters are not nearly as enthusiastic about Clinton as they were about Obama. In 2012, African-Americans were 13 percent of the electorate, and 93 percent of them voted for Obama.
But this year, early-voting rates for African-Americans in states like North Carolina have been below 2012 levels. The Clinton campaign's recent travel schedule shows how seriously it takes this problem. She and her surrogates have held rallies in cities like Philadelphia, Detroit and Cleveland, trying to boost turnout among African-Americans.
On Friday, the Democrats pulled out one of their most powerful surrogates — and no, it wasn't President Obama. Beyoncé showed up at a GOTV rally in Cleveland, joining her husband, Jay Z, and Hillary Clinton. On Sunday, there was another Cleveland rally — this one with LeBron James. Both Barack and Michelle Obama will join Clinton, with her husband and daughter, for a rally on Independence Mall in Philadelphia.
If Clinton can't boost African-American turnout, even with all that help, the question becomes whether she can make up for it with historic levels of support from Hispanics and suburban women.
In 2012, Hispanics were 10 percent of the electorate, underperforming their share of the voting-age population. Mitt Romney got 21 percent of their vote, and Trump has been polling much lower than that. On Tuesday, we will find out if Trump's divisive rhetoric about immigrants has emboldened Hispanic voters.
5. What does the Electoral College map look like?
Democrats came into the race with a structural advantage in the Electoral College. Their big blue wall — the states that Democrats have won in the past six presidential elections — gave Clinton a strong base to build on. If she can win just two of the three big battleground states — North Carolina, Florida and Virginia — she will have shut off Trump's path to 270 electoral votes, even if he wins the other toss-up states.
As those states and others in the South and West become more diverse and educated, they will become harder for the Republican Party — in its current form — to win.
Meanwhile, there are some traditional battleground states — like Ohio and Iowa — that are becoming older, whiter and less educated. That's turning them from true battlegrounds into more reliable red states.
Something else to watch for is the margin of Trump's victory in Georgia and Arizona. If Clinton can come close in those two traditionally red states, it will be because of the diverse, educated populations around Atlanta and Phoenix. And it will be a sign that Arizona and Georgia are on their way to becoming the new battleground states.
6. What happens to the House and Senate?
The Senate is the big prize. Until recently, Democrats felt confident they could get the four seats they needed to take back control if Clinton is in the White House and Vice President Tim Kaine held the tie-breaking vote.
But Senate races have tightened along with the presidential race. Watch to see how many Republican Senate candidates outperform Donald Trump — and how many hang on to their seats in states that he loses. If Pat Toomey of Pennsylvania wins, for instance, it will tell Republicans that their own brand hasn't been hurt too badly by Trump's negatives.
But if Trump drags down a bunch of Senate Republicans, the post-election GOP assessment will be much more pessimistic.
No one is predicting that the Democrats will get the 30 pickups they need to take back the House majority. But if they can get 15 or higher, it will be a very bad night for House Speaker Paul Ryan. Ryan twisted himself into a pretzel by endorsing but not always supporting Donald Trump. Now, he's facing the prospect of a slimmer majority, with fewer moderates. Conservative members in the Freedom Caucus have already sent warning shots threatening Ryan's tenure as speaker.
For Democrats, anything less than 15 net pickups will be a disappointing outcome.