They represent a sliver of the electorate yet could still hold the key to the Oval Office.
In a contest that's already the most expensive in history, we set out to meet the men and women whose choices are so highly prized: the undecided voters.
They represent six key groups in the key swing states where their votes matter most:
A millennial in New Hampshire. A Catholic in Ohio. A long-term unemployed man in Nevada. A Latino in Florida. A single woman in Virginia. An evangelical in Iowa.
We introduced you to them through deeply drawn profiles accompanied by photographic portraits, videos and data visualizations that illuminate the nexus between real life and politics -- the emotional terrain that determines how these ordinary Americans could decide the election.
With less than a day left before the election, we caught up with them to see if they've made up their minds -- and how they came to their decision. Three told who they're voting for, two wouldn't say and one -- well, she's still undecided.
The Millennial: Imagining he's the candidate
The last few months have been especially busy for Tyler York. He's worked 60 hours a week between his three jobs, and he welcomed two nephews into his already big, bustling family.
But the 25-year-old spent a lot of time thinking about the election, too, trying to decide how to decide. He watched the debates and talked to supporters of President Barack Obama and Mitt Romney, but he wasn't satisfied with anybody's answers.
"People my age, people generations older ... I've realized that they don't truly know why they're voting for their guy," he said. " 'You should vote for me because the other guy's bad' isn't really educating anybody on the issues."
A colleague suggested this: Imagine you are the candidate. What are the issues most important to you? What is your stance? And which of the real-life candidates lines up best? Not perfectly, but best?
He spent hours researching the candidates' ideas on foreign policy, a subject he's passionate about after traveling overseas and making friends among the large refugee community around Manchester, New Hampshire.
He read up on energy and the environment, which sparked his interest after teaching a sustainability class at a private school. He was stunned by how little information he found about education; there's a lot of talk about its importance, but no vision from candidates, he thinks. And he studied their stances on women's health, gender pay disparities and same-sex marriage.
York, the undecided millennial, became York, the decided voter -- but he doesn't want to say who he'll support. Sifting through so many out-of-context attacks and meme-making one-liners made him wish for clearer facts, not more noisy opinions.
He still identifies as an independent and can't imagine himself volunteering for a campaign or cause in the future. The moment you do, he said, you stop listening to other sides' points of view, or everyone thinks you do. Obama and Romney are often pretty similar, he thinks. York's not so sure the divisions in politics and parties are real. It's just that loud arguments and snappy comebacks get attention.
That doesn't mean it's easy for any candidate to bring people together, he said.
"If it was a legitimate difference or true barrier, it would be one thing," York said. "But because it's manufactured, it feels like 'I'm not supposed to agree with you.' "
York said he'll spend the days before the election talking to trusted friends and family members whose votes are going the opposite way. He's not sure they could change his mind, but he wants to listen.
"I want to know why they feel so strongly in that direction," he said. "I hope to hear an eloquent argument of why they feel that way.
"I don't need to be reassured of my own opinion. It takes a lot more than watching news or reading articles (to make the decision.) Self-reflection is the most important part."
He's making decisions for himself, too. By this time next year, he still expects to be working all three of his part-time jobs. He's enjoying them, so why stop? He doesn't think he'll still be living above his parents' garage, though. He plans to have a stable income for more than a year by then, and he'll have saved for a healthy down payment on a place of his own -- if he decides to buy.
But he's still not sure he wants to make the commitment.
The Catholic: Looking for the truth
Mary Roberts usually waits until she's attended rallies for both political parties to make up her mind about how she'll vote. Living in the battleground state of Ohio, she has a greater chance of doing that than most Americans -- except for this year.
That's because someone recently hit her car, and it was totaled. Now she attends physical therapy and needs a cane, which has left the normally active 67-year-old feeling frustrated. It's also slowed her decision-making process.
