Michael Hiltzik: How did America get addicted to a policy that fails everyone but the rich?

Here's the central riddle of U.S. politics since the Great Depression:

Social Democratic policies crafted in the 1930s succeeded in creating a long era of widespread prosperity, then suddenly lost its credibility in the mid-1970s. It was replaced by the neoliberalism of Ronald Reagan, which failed to help anyone but the rich, yet still governs American economic policy.

The ascent of neoliberalism and its staying power "is a puzzle," J. Bradford DeLong writes in his magisterial new economic history of the 20th century, "Slouching Towards Utopia." It's the central puzzle that DeLong, a professor of economics at UC Berkeley, a widely followed economics blogger and one of our leading critics of economic inequality, aims to examine.

Delong takes as the canvas what he calls the "long twentieth century," which he defines as the period from 1870 to 2010 and argues was "the most consequential years