Could younger voters actually prevent Clinton from winning the election? Ronald Brownstein addresses the possibility at The Atlantic:

Clinton struggled among Millennial voters in her 2008 primary campaign, her 2016 primary campaign, and in the 2016 general election. Against Donald Trump, Clinton has two big advantages—a policy agenda that polls show largely matches Millennials’ own preferences, and an opponent even more unpopular with them than with the public overall. But she also must overcome her own long history of failing to connect with this growing group of voters—a failure that is increasingly worrying Democrats as the overall race tightens.

“This could very easily be the difference between winning the election or not,” said Andrew Baumann, a Democratic pollster who is regularly polling Millennials during this campaign. “If she ends up with them at 50 percent [of the vote] or 55 percent or 60 percent, those are hugely different scenarios.”

In simplest terms, Clinton’s problem is that large numbers of Millennials have never warmed to her as a national candidate.

Brownstein shares figures showing Clinton’s deficit with Millennial voters vs. Obama in 2008 and against Sanders during this campaign’s primary season, in which Sanders bested her in 25 of 27 primary and caucus states. Brownstein notes that Clinton leads Trump in polls so far, but “show her failing to consolidate the enormous share of Millennials who express unfavorable views about Trump. Instead, many of those voters now say they will support libertarian Gary Johnson or Green Party nominee Jill Stein.” Brownstein shares some poll results:

 A survey of Millennials in 11 battleground states released last week by Baumann’s firm, the Global Strategy Group, for Project New America and NextGen Climate presents the same daunting contrast for Clinton. In that survey, 75 percent of Millennials say they view Trump unfavorably, 73 percent describe him as a “racist,” and 70 percent say he is “unfit to protect our country from major threats.” But among likely voters, this survey again found Clinton drawing 48 percent, to Trump’s 23 percent, 13 percent for Johnson, and 8 percent for Stein.

Brownstein notes that there has been some improvement in Clinton’s poll numbers with younger voters since July. Clinton’s deficit with Millenial voters is apparently not about policy. Clinton supports all of the right policies favored by younger voters, but “Big majorities of Millennials, the polls show, view her as untrustworthy, calculating, and unprincipled.”

It can be argued that young voter turnout rates have not been all that impressive. But close margins in key swing states could make them a pivotal constituency.

As the numbers noted above make clear, it’s not that Millennials prefer Trump: it’s more that too many of them are, at this late date, considering casting their ballots for Libertarian nominee Gary Johnson. Clearly Democrats have work to do to improve Clinton’s credibility and image, but also to educate these voters about Johnson’s right-wing economic policies, which couldn’t be much more detrimental to their interests and prospects.