Second, keep in mind that different polls have different assumptions for what the electorate will look like. Hampton, for instance, models a turnout with a higher-than-usual percentage of men and self-identified Republicans—which, of course, has the effect of helping Trump’s numbers.

Third, it’s possible that we’re seeing realignment in action. Trump appeals to blue-collar voters who once were part of the Democratic coalition, but who have been trending away in recent years. Meanwhile, Democrats have been building a new coalition that relies more heavily on suburban voters and Hispanics.

While Clinton looks to be in trouble in some key industrial states, she appears ascendant in three states where demographics are running in the Democrats’ favor—Virginia, North Carolina, and Colorado.

It’s likely all three explanations are true. There are also at least two other unknowns in this election.

One is: How many people are lying to pollsters? In the 1980s, pollsters discovered that some white voters claimed they were going to vote for black candidates—such as Doug Wilder for governor of Virginia in 1989—but didn’t actually do so. It’s possible that a corresponding “Trump factor” could emerge in 2016.