Beginning with the presidency of Jimmy Carter, a succession of Democratic presidents joined Republicans in turning away from the New Deal model of regulated capitalism toward what has come to be known as neoliberalism. The neoliberal credo claims that markets work efficiently and that government attempts to constrain them via regulation and public spending invariably fail, backfire, or are corrupted by politics. As public policy, neoliberalism has relied on deregulation, privatization, weakened trade unions, less progressive taxation, and new trade rules to reduce the capacity of national governments to manage capitalism. These shifts have resulted in widening inequality, diminished economic security, and reduced confidence in the ability of government to aid its citizens.

The Republican embrace of this doctrine is hardly surprising. Given the lessons learned about the necessity of government interventions following the 1929 stock market collapse and the success of the Roosevelt administration as a model for the Democratic Party, the allure of neoliberalism to many Democrats is a puzzle worth exploring.

The term “neoliberalism” itself is confusing, because for at least a century “liberalism” in the United States has meant moderate left, not free-market right.

 Neoliberalism in its current economic sense draws on the older meaning of liberalism, which is still common in Europe and which holds that free markets are the counterpart of a free and democratic society. That was the claim of classical liberals like Adam Smith and Thomas Jefferson.

Only in the twentieth century, after the excesses of robber-baron capitalism, did modern liberals begin supporting extensive government intervention—the use of “Hamiltonian means” to carry out “Jeffersonian ends,” in the 1909 formulation of Herbert Croly, one of the founders of The New Republic.

 This view defined the ideology of both presidents Roosevelt and was reinforced by the economics of John Maynard Keynes. In Britain, the counterpart in the same era was the “radical liberalism” of social reform put forth by the Liberal prime minister David Lloyd George.

The term neoliberalism also gets muddled because some on the left use it as an all-purpose put-down of conservatism—to the point where one might wonder whether it is just an annoying buzzword. But neoliberalism does have a precise and useful meaning, as a reversion to the verities of classical economics, with government as guardian of unregulated markets.

In his new book, The Rise and Fall of the Neoliberal Order, Gary Gerstle, an American historian who has taught at Sidney Sussex College, Cambridge, since 2014, argues that neoliberalism needs to be understood as a “political order,” which he defines as an era in which a certain set of ideas and policies have become politically hegemonic. “A key attribute of a political order is the ability of its ideologically dominant party to bend the opposition party to its will,” he writes. “Thus, the Republican Party of Dwight D. Eisenhower acquiesced to the core principles of the New Deal order,” just as “the Democratic Party of Bill Clinton accepted the central principles of the neoliberal order in the 1990s.” Gerstle’s lens helps us appreciate the self-reinforcing power of neoliberalism. As government became a less dependable source of economic security, people were made to feel that they were on their own, thus internalizing an individualist rather than collectivist view of citizen and society.