Here's the graph.
The most common age for white Americans last year was 55 -- meaning they were born in 1960, at the tail end of the Baby Boom. In ten years, the most common age for whites will be 65 or thereabouts (depending on how well those years go). In 20, 75 -- and so on. This is the graying of America, the shift toward a much older population that's been forecast for a long time. At some point, the Boomers will make up less of the population of white Americans (sorry, Boomers) and the most common age for whites will jump down a few decades, to that millennial peak that's now at about 24 or so.
But this isn't the only trend that's happening. The most common age for Hispanics in 2015 was 8. In ten years, the most common age will be -- 18, just old enough to vote. In 20 years, they'll be 28 or so -- except that the trend for the Hispanic population has been that there are more young Hispanics than there are old. So the most common age in 10 years might again be 8, or 5 or 11.
We looked at this divide in February 2015. If you take the population of each congressional district that is 56 years of age or older and compare it to the population 25 and under, you get a map for white Americans that looks like this.
This is that same map for Hispanics.
(Bits of Appalachia were missing data.)
By 2050, the Census Bureau predicts, the racial and ethnic composition of the country will look like this.
This is why the Republican party, in the wake of Mitt Romney's loss in 2012 when he took only 27 percent of the Hispanic vote (down from the 31 percent John McCain had won four years earlier), put new emphasis on reaching out to Hispanic voters. If the country is trending more Hispanic, after all, the party would need to bolster how it does with that population if it wants to be successful over the long run. Instead, the party's presumptive 2016 nominee went the other direction -- playing hard for the still-large white vote, which tends to be older and tends to be more Republican.
That strategy may work this year, but it will work less well in 2020 -- and even less well in 2024 and so on. Today's 8-year-old Hispanic will be voting for president for the first time in 2028. Today's 55-year-old white will be 77.
The uncaring nature of human existence means that one of those groups may be a better long-term political bet than the other.