Correction Appended

The clearest explanation yet of the forces that converged over the past three decades or so to undermine the economic well-being of ordinary Americans is contained in the new book, “Winner-Take-All Politics: How Washington Made the Rich Richer — and Turned Its Back on the Middle Class.”

The authors, political scientists Jacob Hacker of Yale and Paul Pierson of the University of California, Berkeley, argue persuasively that the economic struggles of the middle and working classes in the U.S. since the late-1970s were not primarily the result of globalization and technological changes but rather a long series of policy changes in government that overwhelmingly favored the very rich.

Those changes were the result of increasingly sophisticated, well-financed and well-organized efforts by the corporate and financial sectors to tilt government policies in their favor, and thus in favor of the very wealthy. From tax laws to deregulation to corporate governance to safety net issues, government action was deliberately shaped to allow those who were already very wealthy to amass an ever increasing share of the nation’s economic benefits.

“Over the last generation,” the authors write, “more and more of the rewards of growth have gone to the rich and superrich. The rest of America, from the poor through the upper middle class, has fallen further and further behind.”