I wrote a post recently in which I mused about the possible causes of the global populist-nationalist trend. One theory that I didn't mention there is that globalism, like some other lefty movements, has a shelf life. I think Steve Sailer advanced this idea in some form.
Freudianism, for example, is mostly discredited now. It had a run of several decades, and then people started questioning it, picking it apart, laughing at it. The same fate recently befell Chomsky's universal grammar. As I've mentioned on this blog, the quality of public architecture has been rebounding recently. If, architecturally speaking, 1913 was 10 and 1970 was 0, then 2016 was about 2.
Leftism may not be retreating in general. There's transgenderism, gay marriage, intersectionality, etc. But for some reason it periodically retreats on some fronts. Why? Maybe because these fronts start to feel stale to people. The young are always looking for something to rebel against.
Well, that last part doesn't fit well with the current populist-nationalist trend. According to this article, during the primaries Trump got 42.3% of the voters over 65, 41.9% of those between 45 and 65, 37.7% of those between 30 and 44 and 32% of those between 17/18 and 32. Oldsters preferred Trump in the general too.
Same thing for Brexit: "leave" got 25% among the 18 to 24 group and 61% among the over-65 group.
None of the theories of the causes of the nationalist trend that I've seen so far were convincing to me.