Bernie Sanders’s loss in the Nevada caucuses, 47 percent to 53 percent, reveals a very real weakness of his insurgent challenge to Hillary Clinton.

According to entrance polls — which may have had some problems of their own, problems that we’ll discuss shortly — Sanders’s appeal is not broad enough among key groups that traditionally make up the base of the Democratic Party.

He lost among women, blacks, nonwhites, and self-described Democrats. But the loss was even more troubling for his camp than that. He also lost highly educated caucusgoers with postgraduate degrees, both the poorest and wealthiest groups, and moderates. He lost those who saw health care and the economy as the most important issues of the election, even though those are key parts of Sanders’s platform and issues on which he is most eloquent and persuasive.

And perhaps most interestingly, he lost overwhelmingly among people who wanted a candidate who could win in November. Good for him though, only 18 percent of those polled thought electability was the top quality a candidate needed to possess. You only have to look at the Republican winner in South Carolina to understand that this is not an electability cycle, this is a anti-establishment, point-making cycle.