As an economist, I admire the power of the free market. So you might imagine that I am dismayed to hear serious political players, not to mention young people, taking socialism seriously.

I’m not. I don’t find 21st-century socialism any more appealing than the 20th-century variety. Both cut off the great creative force of human freedom. What gives me hope, though, is seeing the academy awaken from the slumber into which it fell in the early 1990s. Serious people declared the “end of history” and capitalism, in the form we...