We all know we live in a democracy. And we all know that in our democracy, inequality is rampant. So the question naturally arises: How do wealthy and powerful people protect their privileges against all those who have the right to vote and might—you never know—reject what the wealthy and powerful want?

According to Nancy MacLean, who teaches history at Duke University, elites have found a better way to serve their cause than the outright reliance on police terror associated with dictators such as Robert Mugabe of Zimbabwe or Rodrigo Duterte of the Philippines. Dictatorships, after all, are unstable. A government powerful enough to terrorize the oppressed could at some point turn around and terrorize the oppressors.

Privileged Americans prefer a safer method, one steeped in our history, and in particular the history of the Southern states: Simply prevent those at the bottom from exercising their right to vote at all. Restricting the franchise remains popular in places like North Carolina and Texas, and has recently moved north into Wisconsin, where new voter ID laws meant that by the 2016 election, 300,000 registered voters found themselves without the identification required to cast a ballot. But while voter suppression offers many advantages to elites, it is far from foolproof. We still have courts, and many of them look askance on such schemes. Administrations can respond by appointing a raft of new judges, as the Republicans have tried to do, but that requires continuous occupation of the presidency, which the Republicans have not (yet) been able to accomplish.

Here is where the economist James McGill Buchanan made his major contribution to American political life. As MacLean tells us in Democracy in Chains, Buchanan, a Tennessean who spent most of his career in Virginia, came up with a way to prevent challenges to elite rule so innovative that it deserved a prize. As it happens, he got one: the Nobel Prize in economics in 1986. Buchanan is known for his contributions to what is called public choice theory, which applies economic reasoning to problems traditionally studied by political scientists. The key insight of public choice theory is that there is no such thing as a disinterested public bureaucracy that carries out neutral policies devoted to the common good. “Each participant in the political process,” Buchanan believed, “tries, single-mindedly, to further his own interest, at the expense of others if this is necessary.” Bureaucrats will inevitably try to expand the scope of what they regulate, just as businessmen will seek to expand their profits. Legislators find themselves at the mercy of government administrators because the administrators tend to have only one interest—protecting their turf—while elected representatives have many.

Following this logic, public choice theorists treat government itself with skepticism. If you start hearing terms such as “government failure” or “rent-seeking behavior,” you are likely listening to a public choice theorist. Rent-seeking occurs when individuals or groups seek to obtain favors from government that only benefit themselves, while all taxpayers pay for it. Agricultural price supports are a typical example; so are licensing laws that make it difficult for a funeral director or barber to set up shops that would compete with existing ones. Government failure simply means that an outcome that could be produced more cheaply and efficiently by the market is instead produced by government at greater cost and inefficiency.

The importance of public choice theory, however, lies not in its technical terminology, but in its overall impact as a way of thinking about government. Over the past few decades, disdain toward government has become an established feature of the American political system. By building an influential base of support among academics for curbing the power of the government, Buchanan made a significant contribution to this change in the national mood. And since government has often acted, at least since the New Deal, to protect those with little power from those with more, public choice theory has helped along the process by which inequality in America has risen so dramatically in recent years. ...