Distributed by year of age, the country’s population looks like this. There are about 4 million people at every age until you get to retirement age, when the population at that age starts to drop off. (We’ve indicated the divider between 17 and 18 years of age on this chart, because that will come up later.)

(Philip Bump/The Washington Post)

(No extra credit will be given for spotting the baby boom.)

Thanks to the Census Bureau, we can break out each of these ages by race and ethnicity, if we want to. I wanted to; the result looks like this.

(Philip Bump/The Washington Post)

At a glance that, too, seems about right. Looking at the 40-to-60-year-old range, it looks as if there are more white than nonwhite Americans, which is accurate. But head in one direction or the other, and things look different. Compare the distribution at age 80 with the distribution at 0, for example. Lots more white people at 80; a much more even split among the youngest Americans.

So let’s look at it another way. Here’s the white/nonwhite split by year of age.

(Philip Bump/The Washington Post)

This, in a nutshell, shows the coming shift in American politics. An about-even split among those under voting age. A 55-to-45 split until we get to the mid-40s, when the density of the white population begins to increase. Among older Americans, whites outnumber nonwhites 3 to 1.

There’s variation within that nonwhite group, too. Most of those younger nonwhite Americans are Hispanic. About a quarter of the population younger than 18 is Hispanic. As we reported in July, the distribution of ages for Americans varies widely by racial and ethnic group. Among whites, the most common age is 58. Among Hispanics, it’s 11.

(Philip Bump/The Washington Post)

Why’s that shift important? In part because white Americans tend to vote more heavily Republican. There’s overlap here with the fact that white voters also tend to be older, but even younger whites are more likely to be Republican than are nonwhites.

(Philip Bump/The Washington Post)

The overlap of age and whiteness manifests in another way. Whites and older voters are more likely to vote than are nonwhites and younger people. This overlaps with other factors, too, like homeownership and income. But the effect is clear.

(Philip Bump/The Washington Post)

What’s more, white people tend to be overrepresented among the pool of registered voters. Comparing identifiable racial and ethnic groups from the national voter file (via L2), you can see that whites make up a higher percentage of the voter pool than the actual population, particularly at younger ages.

(Philip Bump/The Washington Post)

There are concrete reasons for that divide. Not every resident of the United States is eligible to vote, of course. Immigrants who aren’t naturalized, for example, can’t cast a ballot in a federal race.

But that registration-population split continues to mean an imbalance in the political power of white Americans. Especially when combined with those higher turnout rates.