David Bell notes that"the theme of 'America’s decline' had in fact been a constant in American culture and politics since at least the late 1950s." Drum expands on that thought:
[W]hat's remarkable, really, is how little America has declined. We are perpetually astounded that our military might doesn't guarantee us instant victory anywhere we go and that other countries are routinely able to make trouble for us, but that says more about our national psyche than about our actual global influence or military power. If anything, our ability to project power may be greater today than it's ever been, and it's certainly greater relative to other countries than it was 50 years ago. Economically, our share of GDP fell surprisingly little in the postwar era, from 28% to about 22%, and has stayed very nearly flat since 1980. And political idiocy aside, our ability to lead the world in a rebound from a world historical financial crash has actually been pretty impressive.
Yglesias pines for relative American decline.