It’s looking increasingly like Hillary Clinton’s struggles with young voters could prove a far more important challenge in Campaign 2016’s final stretch than many expected — and it may prove a decisive one, too. This week’s Quinnipiac poll found that Clinton’s share of young voters drops off sharply when the polling includes Gary Johnson and Jill Stein, meaning they may take a big chunk of those voters, leading data types like David Wasserman and Nate Cohn to warn that this could help cost her the election.

The Clinton campaign knows this is a big problem. She is set to give a big speech next week pitched directly to younger voters. Bernie Sanders and Elizabeth Warren are set to campaign for her in Ohio. And today it emerged that the Clinton campaign has been trying to enlist Al Gore to campaign for her, in hopes that he can win these voters by emphasizing that she takes climate change and climate science seriously, while Donald Trump thinks all of it is a big hoax.

There are various explanations floating around as to the real roots of Clinton’s problems with these voters. Democratic strategists told Bloomberg’s Sahil Kapur this week that a major problem is that they just don’t trust her, and also don’t feel any particular party loyalty. Those strategists also think young voters have not fully grasped the stakes of this election, and may move towards her in greater numbers once they understand that Clinton is far more in line with them than is Donald Trump on issues such as college affordability, the minimum wage, environmental racism, police reform, and climate change.

The polling, as it happens, bears this out. The advocacy group NextGen Climate this week published a poll of over 1,600 voters aged 18-34 in 11 crucial battleground states, and found what looks like evidence of this dynamic. This is captured in the chart below. The poll, which was taken during the last two weeks of August, found that a sizable percentage of these voters still see “no difference” between Trump on major issues (the column in purple on the right):

Those are troublesome numbers for Clinton. However, the silver lining here is that since the group’s poll in July, there’s been some movement in Clinton’s direction on some of these issues (see the column on the left in blue, and the green boxes showing the shift), such as women’s health, equal pay, and the environment.

More broadly, the poll also found that the percentage of these young voters who don’t see any difference between the two candidates “on the most important issues” in general has dropped from 36 percent to 29. Meanwhile, the poll also found that Clinton’s advantage over Trump among these voters in the topline matchups grew by similar amounts — from an edge of 19 points in July, to an edge of 25 points in August — perhaps suggesting a connection between that movement in her direction and more awareness of her positions on issues.

“The big news here is that the more millennials learn about the policy differences between Clinton and Trump, the more they support Clinton,” Jamison Foser, a senior adviser for NextGen Climate, emails. “There’s a challenge for Clinton — too many millennials still don’t see a difference — but that also presents an opportunity for growth via increased efforts to talk to millennials about policy.”

The efforts to close that gap begin in earnest next week. No question, there is a lot of work for Clinton to do on this front. But the Clinton campaign appears to understand that.