About 18 percent of American voters have not made up their minds between Kamala Harris and Donald Trump, recent polls suggest.

Some members of this 18 percent say they lean toward one of the two candidates without having a firm preference. Others say they don’t lean toward either. Yet history suggests that many of these Americans will vote — and will ultimately support the Democratic or Republican nominee. Once they do, they will probably decide the presidential election.

In today’s newsletter, I’ll offer a portrait of the country’s uncommitted voters.

Young moderates of color

A major problem for President Biden’s re-election campaign was his weakness among young voters and voters of colors. A Democratic candidate typically needs to win these groups in a landslide, and Biden wasn’t on pace to do so. Harris is faring much better, which is why the race seems virtually tied. (Nate Silver’s forecast model calls Trump a slight favorite because Trump is stronger in swing states than he is nationwide, while The Economist’s model considers Harris’s national lead large enough to make her a slight favorite.)

Still, even with Harris’s progress among younger voters and those who are Asian, Black, Hispanic or Native American, many remain undecided. As a group, the uncommitted 18 percent of the electorate is less white and younger than decided voters, New York Times/Siena College polling shows:

If you assume that most swing voters are disaffected liberals because of their youth and diversity, however, you will be wrong. For one thing, uncommitted voters are slightly more likely to be male than decided voters are. Most also do not have a four-year college degree, and working-class voters tend to be more socially conservative.