That's pretty much the message of this week's graphic from the Public Religion Research Institute. What you're looking at is the current religious layout by adult generations.

The news is that white evangelicals, mainliners, and Catholics go from 69 percent of those 65 and older to 25 percent of those 18 to 29. And the "unaffiliated" -- i.e. those who say they have no religion -- go from 11 percent of the over-65's to 31 percent of the 18-29's.

All other groups more or less hold their proportional positions except for Latino Catholics and Protestants, who go from six percent of the over-65's to 17 percent of the 18-29's.

There are some important political implications here. White evangelicals vote roughly 3-1 Republican, while Nones vote roughly 3-1 Democratic. And by generational cohort, the percentage of white evangelicals is inversely proportional to the percentage of Nones in the population. Assuming that generational political identification doesn't change, the Nones will in due course have the throw-weight for the Democrats that the evangelicals have had for the Republicans over the past generation.

Add Mormons to the white evangelicals, mainliners, and Catholics and you get 71 percent of the over-65's in majority-Republican ethno-religious traditions. Add up everyone else (except the two percent who won't say or don't know) and you get 70 percent in majority-Democratic ethno-religious traditions.

In other words, a generational freight train is bearing down on the GOP.