New Hampshire is emblematic of a larger Clinton problem. The youth vote was one of the pillars of the Obama coalition. But thus far it’s proven perhaps the most difficult one for Clinton to rebuild. Polls show the nominee failing to earn the confidence of young voters—only 33 percent of those between ages 18-29 told Gallup this month that they approved of her—and running far behind where she would hope to be against her Republican opponent. The polls also show Clinton currently winning under half their votes, while Obama got over three-fifths of that demographic in both of his campaigns.

There are, however, emerging hints of a shift toward Clinton. One group tracking the movement of so-called Sanders holdouts in the general election is NextGen Climate, which is working with labor unions on a super-PAC created to boost Democrats. In August, their pollsters found that 15 percent of young voters surveyed across the country would back Sanders in an imaginary four-way presidential race, but did not back Clinton when she was offered in his place. That represented a five-point drop from July, a possible indication of the influence that Sanders and Elizabeth Warren may have had from their prominent perches on the first night of the Democratic convention. Still, an analysis by the progressive strategy center Project New America found that in a number of battleground states—including Ohio, Florida, and North Carolina—the Sanders holdouts likely constitute a constituency larger than the margins that decided the 2012 presidential race. They also represent a source of lost activist energy for the Democratic ticket: Nestled within Sanders’ approximately 12 million votes were 2.5 million donors.

Traces of those holdouts may be even more evident in the northern tier of states—Sanders won every state that abuts Canada, except for Clinton’s home state of New York. These states share more than latitude: New Hampshire, Maine, and Minnesota are among the most homogenous of the battlegrounds. In comparison, the percentage of black Americans nationwide is twice as high as it is in Wisconsin, which has the most racially mixed population of these Sanders states. In large, diverse states, an effective mobilization campaign can make up for a lack of enthusiasm among youth voters.