The demographic and support shifts at the core of Donald Trump’s electoral problem

One of Donald Trump's more famous comments about his support came the evening of the Nevada caucuses in February.

Donald Trump – who has always been an unfiltered candidate – said he loves "the poorly educated" during his Nevada caucus victory speech on Feb. 24, 2016. (Video: Peter Stevenson/The Washington Post)

"We won the evangelicals," Trump said. "We won with young. We won with old. We won with highly educated. We won with poorly educated! I love the poorly educated!"

Trump was talking only about groups he won within the Republican electorate, but that last point is true. Trump and voters without a college degree have formed a mutual admiration society over the course of the campaign — at least white male voters without a college degree. In 2012, those voters backed Mitt Romney by 31 points, according to exit polls. In the most recent Washington Post-ABC News poll, Trump led with the group by 42 points.

For Trump, that's the good news. The bad news is that, as a share of the electorate, the number of white men without college degrees who come out to vote has been declining for years. The worse news is that all other combinations of education and gender among white voters are more supportive of the Democrat this year than they were four years ago — sometimes by a wide margin.

Looking at exit polling since 1980, we can see how the electorate has evolved as a function of both its educational/gender/racial breakdown and how those groups voted.

In the charts at the bottom, you can see the shift toward Trump for white men without degrees. The graph at top shows how that group, once more than a quarter of the electorate, has slipped to 16 percent as of 2012. College-educated white women, though, are now more of the electorate — and favor Hillary Clinton by 19 points, a change of 25 points. (White men without degrees are only 11 points more supportive of Trump than Romney, according to our most recent poll). The number of nonwhite voters with and without degrees was too small to break down by gender in our poll, but their support for the Democratic candidate has been consistent. So has the growth of the nonwhite vote in the electorate.

The divergence between white men without degrees and white women with degrees is more obvious here, plotting three dimensions of information: percent of the electorate (circle size) versus year of election and margin of support. Note how big the red and purple outlined circles were in 1980 relative to 2012. That's the decline in the density of the white vote without degrees.

One more way of looking at it: We can trace margins of support by election relative to density of each group in the electorate. White women with college degrees used to be a small percentage of the electorate. As more of them began to vote, they were more likely to support Democrats. In 2012, the group backed Romney — but in 2016 are poised to shift far to the left. White men without degrees are moving down and to the right: Less of the electorate, more Republican.

But again, Trump needs to do better than Mitt Romney, not just match him. Forty percent of the electorate in 2012 was white women, among whom Trump is doing much worse than Romney. If that holds, he has to vastly increase turnout among white men — perhaps turn out more than actually exist in any practical sense.

This is why Trump is trying to rebuild his support with white women, why his campaign has showed lenience on immigration (sporadically) and why he's trying to prove that he's not biased or sexist. If he can't get those white women back on board, this thing is done.

Emily Guskin contributed to this report.