The single biggest threat to Republicans' long-term viability is demographics.

The big picture: The numbers simply do not lie. America, as a whole, and swing states, in particular, are growing more diverse, more quickly. There is no way Republicans can change birth rates or curb this trend — and there's not a single demographic megatrend that favors Republicans.

Why it matters: President Trump’s short-term calculation to stir up white voters with race-baiting rhetoric might very well echo for a generation.

About last night: Trump paused while speaking at a "Make America Great Again" campaign rally in Greenville, N.C., to savor supporters' new roar: "Send her back!"

"I have a suggestion for the hate-filled extremists who are constantly trying to tear our country down," Trump said. "They never have anything good to say. That's why I say, 'Hey if you don't like it, let 'em leave, let 'em leave.'"

The context, from AP: "Not since George Wallace's campaign in 1968 has a presidential candidate — and certainly not an incumbent president — put racial polarization at the center of his call to voters."

For any Republican thinking past 2020, here are numbers to fear, reported by Axios' Stef Kight:

The Hispanic share of the population has grown in every state since 2000, according to Census data.

Hispanic people now make up a quarter of the population in Florida, almost a third of the population in Arizona and 39% of Texas — all Trump states in 2016 that are becoming more winnable by Democrats.

Florida and Texas, two of the big electoral giants that voted for Trump, are witnessing the fastest non-white population growth.

This wave is only accelerating, as Stef reported in "America's majority minority future":

Next year, the entire under-18 population will be majority non-white, according to Brookings demographer William Frey.

In less than a decade, the under-30 population will be majority non-white.

Between the lines: Trump clearly thinks this is good short-term politics.

Truth is: It's unknowable, though highly debatable.

Long-term, it seems unambiguous: If you need more African American and Hispanic voters, maligning and marginalizing them strikes even some inside this White House as stupid politics.

Go deeper: A tough time to be a Trump supporter