The youngest cohort of voters was famously on fire for the Bern. They are not warming to Hillary Clinton as much as she might hope. Photo: Chip Somodevilla/Getty Images

One of the important aspects of this presidential election has been the enormous assistance Donald Trump has provided to Hillary Clinton in nailing down the support of minority voters. It had been assumed going into the cycle that a white Democratic nominee would not be able to match Barack Obama’s historic performance among African-Americans, and that Republicans would almost certainly be able to improve on Mitt Romney’s terrible numbers among Latinos. Wrong and wrong, with Trump on the ballot.

But there’s another element of the Obama coalition that has not warmed up to Hillary Clinton as much as she might hope, mostly to the benefit of third- and fourth-party candidates: young millennial voters. A new analysis of under-25 voters by FiveThirtyEight’s Harry Enten using a very large sample provided by SurveyMonkey shows them offering strong approval of Barack Obama’s job performance (a net-positive 32 percent) but at the same time giving Clinton much less than half of their votes (41 percent for Clinton, 27 percent for Trump, 17 percent for Johnson, 10 percent for Stein).

The same source shows Clinton benefiting greatly in this demographic from a shift to a two-way race, so if Johnson and Stein could be relied upon to fade in the stretch as minor candidates usually do, it could represent a critical reservoir of hidden support for the Democrat. But so far the minor candidates show no sign of losing support.

Is this all a hangover from the Democratic primaries, in which younger millennials were the red-hot core of the Bern? Perhaps to some extent. A new ABC/Washington Post survey shows 18 percent of former Sanders voters now supporting either Johnson or Stein. But this may be confusing cause and effect: Clinton’s very limited appeal to young voters that manifested itself in a poor performance among millennials in the primaries may just be carrying over to the general election. It’s also interesting that she’s doing better among older millennials — more likely to be literal members of the Obama coalition — than the younger cohort. The older they are, the more likely they are to vote, at least based on prior experience.

Enten calculates that if under-25 voters support Clinton as much as they approve of Obama, it would add two points to her overall vote. That’s a lot in a close election. Perhaps the Clinton campaign has in mind some targeted appeal to these voters going down the stretch. It might want to start by getting some pointers from Bernie Sanders on how to avoid letting age and perceived health risks become a problem with voters too young to know what it’s like to become “overheated.”