Obama beat Clinton by 20 percentage points among voters younger than 30, while she beat him by 25 points among voters older than 65, according to a cumulative analysis of the results of all the exit polls in the 2008 Democratic primary conducted by ABC pollster Gary Langer. Voters in the middle-aged groups divided more narrowly: Obama carried those aged 30-44 by 11 points, and Clinton carried the near retirement generation (45 to 64) by seven, according to Langer’s analysis.

But when it comes to piling up votes, one of these demographic advantages is much more useful than the other. Across all of the 2008 contests, according to Langer’s calculations, voters older than 45 cast fully 61 percent of Democratic votes, while those younger than 45 cast 39 percent. That’s an advantage for Clinton. And it’s a slightly worrisome note for Sanders—a cloud passing on an otherwise sunny day—that young voters cast a slightly smaller share of the total Iowa Democratic vote in 2016 than 2008.

Still, Sanders’s overwhelming margins among Iowa’s younger voters—which exceeded even Obama’s 2008 showing—affirmatively answered the first critical question for the Vermont senator’s campaign: Would the connection with young voters evident at his rallies translate to the ballot box?