Increasingly American politics are driven by generational change. The election of Donald Trump was not just a triumph of whiter, heartland America. It also confirmed the still considerable voting power of the older generation. Yet over time, as those of us who have lived long enough well know, generations decline, and die off, and new ones ascend.

In this past election, those over 45 strongly favored Trump, while those younger than that cast their ballots for Clinton. Trump’s improbable victory, and the more significant GOP sweep across the country, demonstrated that the much-ballyhooed millennials simply are not yet sufficiently numerous or united enough to overcome the votes of the older generations.

Yet over time, the millennials—arguably the most progressive generation since the ’30s—could drive our politics not only leftward, but towards an increasingly socialist reality, overturning many of the very things that long have defined American life. This could presage a war of generations over everything from social mores to economics and could well define our politics for the next decade.