First-graders at Birdwell Elementary School in Tyler, Tex. (Andrew D. Brosig/Tyler Morning Telegraph via Associated Press)

William H. Frey, a senior fellow at the Brookings Institution and a population-studies professor at the University of Michigan, is author of “Diversity Explosion: How New Racial Demographics are Remaking America.”

This month in Evenwel v. Abbott, the Supreme Court heard arguments for altering the long-standing principle of “one person, one vote” by substituting voting-age citizens for total population when drawing legislative districts within states. While much has been said about the implications of eliminating noncitizens from the population on which district lines are based, a ruling in favor of the plaintiffs in this case could have an even larger impact: shortchanging the interests of minority children and their families. That’s because nearly half of the nation’s under-18 population is made up of racial minorities, while 70 percent of voting-age citizens are white. The United States is undergoing a boom in demographic diversity, but it’s the younger population that’s being transformed first.

Removing the racially diverse youth population from the apportionment calculation would intensify a divisive cultural generation gap that pervades politics and public attitudes in this country. Pew Research polling has shown that the mostly white older population is far less accepting of immigrant minorities and government support for social programs than is the increasingly minority younger population. The rise of immigrant-bashing presidential candidate Donald Trump as a hero among older white Republican primary voters represents an extreme version of the pushback against a demographically changing country.

Even without limiting state redistricting to adult citizens, numerous state-level representatives come from districts that are, overall, older and whiter than the population in general. A redistricting scheme that omits children as well as adult noncitizens from the equation will add to the number of rural, whiter, outer suburban districts — creating an even greater disconnect between the voting constituencies of elected representatives and the total population, 23 percent of which is children. This would almost certainly result in a reduction of support for state-subsidized programs in areas including education and health care as well as assistance for low-income families.

Additionally, treating only voting-age citizens as “persons” for purposes of drawing legislative districts would have the greatest negative impact on states that can least afford it — those where young minority populations are large and increasing. Between 2000 and 2014, Texas — where this case originated — led the nation in the net gains of children under age 18. Racial minorities now make up 67 percent of Texas’s children, compared with its 54 percent white-citizen voting-age population. Because these children are concentrated in certain parts of the state, a redistricting plan based on the residential patterns of only adult citizens will inevitably slight the interests of these children and their families.

Texas is one of 25 states that registered gains in their (increasingly minority) child populations since 2000. These generally fast-growing states contrast with the 25 states that sustained absolute losses in their number of children — slower growing, older or whiter states. Together, the first group of states represents the emerging training ground for tomorrow’s labor force, where state initiatives to benefit young children, and especially Hispanics, blacks and other minorities, are crucially needed. Yet these are the very states that would be affected most if adult citizens were the basis of redistricting.

Florida, North Carolina, Georgia and Arizona come after Texas among the states recording the largest gains in their under age-18 populations since 2000. In each case, minorities account for all of those increases. What these states also have in common is a need for greater resources to advance the welfare of their children. A recent assessment of child well-being compiled by the Annie E. Casey Foundation that takes into account multiple measures of education, health, economic and community conditions, ranks Texas 41st, with Florida, Georgia, North Carolina and Arizona also ranking in the bottom third of the 50 states.

Let’s hope that the Supreme Court will weigh these effects on the next generation when rendering its decision in Evenwel v. Abbott. The nation is undergoing an unprecedented demographic transformation wherein minority growth is driving population growth, especially among the youth population. This is more than just an interesting statistic. It reflects the fact that the next generation of workers, community leaders and voters must be prepared to contribute to a society and economy that will undoubtedly be different from that experienced by today’s voting-age citizens.

We are at a crucial juncture, and navigating it is made all the more difficult by the cultural generation gap that pervades the nation’s politics. If there was ever a time when the needs and interests of the next generation should be fully included in state and local decision-making, this is it.