Many advocates of what I have called the “progressive theory of mobilization” assume that the typical nonvoter is young, brown or black, and very progressive. But while, of course, some nonvoters fit that description, an overwhelming majority don’t.

Nonvoters are, in fact, somewhat more likely than voters to be brown or black: While 10 percent of voters are black, 13 percent of nonvoters are. And while 11 percent of voters are Hispanic, 15 percent of nonvoters are. But among nonvoters, the overall share of people of color is quite small: Nearly two out of every three nonvoters are white.

Nonvoters are also far less progressive than is commonly believed. They are more likely than voters to support constructing a wall on the southern border with Mexico, less likely to support a path to citizenship for undocumented immigrants, less likely to support abortion rights, and less likely to favor gun control. Nonvoters do skew left on some important economic issues, such as support for a higher minimum wage. But on the defining cultural issues of the moment, they are markedly more conservative.

In light of their views on public policy, it is hardly surprising that nonvoters are not particularly likely to describe themselves as liberal or to say that they favor the Democratic Party. Among voters, 38 percent consider themselves Democrats and 30 percent Republicans, for a differential of eight points. Among nonvoters, 31 percent consider themselves Democrats and 26 percent Republicans, for a differential of only five points. The ideological breakdown of nonvoters is even more revealing: A clear majority of them consider themselves either moderate or conservative; only one in five say that they are liberal.

Nor is there much evidence that nonvoters are particularly energized to remove Donald Trump from office. They are less likely than voters to say that the country is going in the wrong direction or to believe that the upcoming election holds more importance than previous ones. And whereas 46 percent of all voters say that they are likely to vote for the Democratic Party’s nominee, only 33 percent of nonvoters say they’ll vote this way if they choose to go to the polls.

Peter Beinart: Regular Democrats just aren’t worried about Bernie

The best way to understand nonvoters, the authors of the Knight Foundation study suggest, is to divide them into two broad camps. Nearly half of them simply have little interest in politics; when they record opinions about politics at all, they rarely fall into a clear ideological camp. A little more than half do have a more determined set of political preferences. But, like the American electorate as a whole, this group is almost evenly split among three different ideological groups: progressives, moderates, and conservatives.

It is natural for ideologues of every hue to project their hopes and aspirations on the reservoir of voters who rarely show up to the polls.