It’s fairly well established that much of the reason former vice president Joe Biden leads the 2020 Democratic presidential primary field is because Democrats think he is the best bet to beat President Trump.

We’ve assessed this before, noting that some part of this argument seems to be rooted in the popular understanding of why Hillary Clinton lost in 2016 (Biden can win whites in the Midwest!). A new poll from Monmouth University, though, offers a different insight on the question: how electability varies by demographic — and how those differences overlap with candidate choice.

As usual (at the moment), Biden leads in the Monmouth survey, with support from a third of the registered voters surveyed. Sen. Bernie Sanders (I-Vt.) comes in second with 15 percent, followed by Sens. Kamala D. Harris (D-Calif.) at 11 percent and Elizabeth Warren (D-Mass.) at 10. Only three other candidates get over 1 percent support in the poll: South Bend, Ind. Mayor Pete Buttigieg (6 percent), former Texas congressman Beto O’Rourke (4 percent) and Sen. Amy Klobuchar (D-Minn) (3 percent).

In the field, there are broad differences in support among demographic groups. For example, Sanders does 8 points better with men than women, while Biden does 10 points better with women than men. (On the charts that follow, candidates are stacked so that candidates doing better overall are positioned on top of those doing more poorly.)

The Sanders-Biden difference is particularly stark in terms of age. Sanders does 21 points better with voters younger than 50; Biden does 14 points better with voters 50 and older.

On race, Biden performs better with nonwhites by 10 points — the same margin by which Warren does better among white voters.

Warren also does significantly better among voters with a college degree. Both Sanders and Biden do slightly better among those without a degree (in part because Warren eats up so much more of the pool of better-educated respondents).

Where Biden’s support has consistently set him apart from the field is among more moderate voters. He does 19 points better with those respondents than with more liberal ones, according to Monmouth’s polling.

At times, that support from moderate Democrats has been overlaid with Biden’s electability argument. He’s the safe bet, that line of argument goes, not proposing anything too outrageous, the safe harbor in the storm. That’s part of why Democrats think he’s more viable — and that’s helping to power his poll numbers.

Monmouth asked another question that gets to that point.

“Which type of candidate would you prefer,” the pollsters asked, “if you had to make a choice between: a Democrat you agree with on most issues but would have a hard time beating Donald Trump or a Democrat you do NOT agree with on most issues but would be a stronger candidate against Donald Trump?”

In other words, do you want a nominee that’s a sure thing but who has policy priorities you disagree with, or do you want a candidate with whom you agree but who might have a trickier time beating Trump?

Most voters picked the sure thing. In fact, they preferred a candidate with whom they might not agree on policy by a 24-point margin. Interestingly, that margin was about the same among both liberal and moderate respondents, meaning that both groups were willing to give up policy goals if it meant beating Trump.

That agreement vanished, though, when looking at gender and age splits.

Among men, preference between the two hypothetical candidates was about even. Among women, though, beating Trump took priority by a 39-point margin. A slightly smaller gap existed by age. Younger voters were more likely to say that policy priorities were important. Older respondents preferred the more electable candidate by 36 points.

Now scroll back up to the charts with the little faces. Among women, Biden does 10 points better than men. Among older voters, he does 14 points better.

He does better, in other words, among voters more worried about electability. Here, that’s not a function of ideology.

It’s probably not a coincidence that older Democratic women have consistently been the leading edge of opposition to Trump’s presidency. That’s shown up in polling and was reinforced in an informal survey of anti-Trump activists in April 2017.

Monmouth’s polling suggests that this energy has boosted Biden’s candidacy. But a word of warning: We’ve pointed out before that electability is a fickle thing. That’s probably especially true for a candidate with a history of making significant stumbles on the campaign trail.