David Brooks notes that "if you grew up in a big city in the '70s, then life is better for you now in every respect." But this also means that if you grew up in a big city in the '70s, you came of age in a time of crime, drugs, riots, a lost war, and family collapse. If you grew up near a big city in the '70s, as David Brooks did, as I did, the spectacle of the terrible things happening nearby and Coming For You Next was, if anything, even scarier than if you lived within it and learned how to cope with real dangers.
Your worldview is shaped by what was going on when you first started noticing the world. Even if the actual world gets much better - as it has for young Boomers and old Xers - your adolescent worldview tends to stick with you. The generation that came of age in the 1970s, what Doonesbury rightly called "a kidney stone of a decade," are now coming to power.
I think the fear that drives much of American politics now is not driven by real threats of today. They are driven by the scary conditions that prevailed in the childhood and early adolescence of today's rising ruling cohort.