America is getting less white a lot faster than the Republican Party. That trend threatens to be a problem over the long term for the GOP.

When Donald Trump told an interviewer last week that Republicans would never win another election if Hillary Clinton triumphed in November, we took a look at the heart of his claim. Clinton would give blanket citizenship to millions of immigrants, Trump asserted, throwing elections to her party thanks to all those new Hispanic voters. But we pointed out that the demographics of the country are already headed that way.

New data from Pew Research makes this point more clearly by looking at past trends.

Since 1992, Pew estimates that the density of nonwhite voters in the Republican Party has doubled from 7 to 14 percent. In the Democratic Party, the increase has been a bit less than double — but it's substantially larger as a percentage of the party. The density of nonwhite voters in the Republican Party in 2016 is still only a little more than half what it was for the Democrats 24 years ago.

But the density of nonwhite voters in the electorate has just about doubled, too. The Democratic Party is getting less white faster than the voting population; the GOP is getting less white a lot more slowly.

The GOP is now about as diverse as the electorate was when Bill Clinton first won the presidency.

What's happened to the GOP, as my colleague Aaron Blake wrote on Tuesday, is that it has increasingly become the domain of older white men without college degrees. (In 1992, 38 percent of Republicans were 50 or older; in 2016, the figure is 58 percent.) The graph at the top of this post suggests that this might be less of a problem for the party, given that the number of older whites in the population will also increase.

The challenge is that younger white voters — the people who will be 65 by 2060 — are more likely to identify as Democrats than older whites.

White millennials (defined by Pew as being born in 1981 or later) identify with or lean toward both parties equally. Among Gen Xers (born 1965 to 1980), the GOP has a 15-point advantage. Among boomers, it's 20 points. Millennials who aren't white are also more likely to be Democratic by a wide margin but with less of a difference from older nonwhite voters.

There's some variation in party identities over time, but the Democrats are starting from a position of advantage. Research suggests that political beliefs usually form early, with events by the age of 18 being more influential than events later in life. All of which suggests that the tie ballgame with white voters coupled with the wide Democratic advantage among nonwhites as the electorate grows less white is a significant long-term problem for the Republican Party.

Political parties can change (which helps drive some of that movement in the charts above). We remember that the GOP outlined a plan to reach out to Hispanic voters after Mitt Romney's loss in 2012. The only problem was that the existing base wasn't enthusiastic about it, so much so that the current Republican nominee is much more fervently opposed to immigration reform than Romney was.

An optimistic way to look at that: Things can change fast. This should offer the GOP some reassurance.