Presidential candidates go hard after millennial voters because they know they have the power not just to shape, but to sway, entire elections. The voting bloc has already proved it's a powerful force: In the primaries, former Democratic candidate Bernie Sanders won over the millennial vote in a landslide, earning more votes from people under 30 than both Hillary Clinton and Donald Trump combined.
Harvard University professor of government Stephen Ansolabehere said Sanders' popularity with millennial voters set the tone for their importance in the general election.
"The primaries put pressure on Clinton to appeal to those voters," Ansolabehere said. "Sanders won with millennials by focusing on college debt, and the Clinton campaign pivoted to embracing that issue really readily."
Now that Clinton is head-to-head with Trump, it seems she's claimed many of Sanders' millennial supporters for herself. As of mid-September, Clinton was leading Trump 48 to 23 with Americans aged 18 to 34, NBC News reported, referencing a poll from NextGen, which is run by Clinton supporter Tom Steyer. Other polls showed Clinton claiming a smaller margin of millennial voters, as many lean toward third-party candidates.
Ansolabhere said millennial voters were "up for grabs" following the primaries, but the Trump campaign didn't make any concerted efforts to sway them — which could be a problem not just for Trump, but for the entire Republican Party.
"People really anchor their political histories for the rest of their life from their first election, and we've seen that for every generation," Ansolabehere said. "Now there's a whole generation of people who are more Democratic and throughout their life they're going to vote that way."
While many people have written off millennials as "apathetic," especially when it comes to politics, Ansolabehere said voters aged 18 to 34 are flipping that stereotype on its head. He said millennials have been voting at higher rates in their first election than baby boomers had when they came of age, a trend that crystallized in the 2008 and 2012 elections.
A November 2012 Politico article reported about half of all eligible people in the 18-to-29 age range voted in that year's presidential election — "roughly the same level as 2008." In many ways, that voter bloc helped elect and re-elect President Barack Obama.
"Obama won at least 61% of the youth vote in four of those states, and if [Mitt] Romney had achieved a 50-50 split, he could have flipped those states to his column," Politico reported, citing a Tufts University study. With at least 80 electoral votes depending on youth, according to the study, Politico said Romney would have "cruised to the White House" with ease if he had managed to split the millennial vote with Obama.
"The question in 2016 is whether that's going to continue or whether it was motivated by enthusiasm over Obama," Ansolabehere said. "But I think it's a characteristic of the generation."