In the last few years, social science has provided documentation for what has long been obvious to informed observers: the degeneration of American and Western democracy into a species of plutocracy. In his bestselling “Capital in the Twenty-First Century,” Thomas Piketty has documented the decline and rise of inequality and the prospect of a return to “patrimonial capitalism,” or political and social domination by possessors of great wealth. At the same time, scholars like Martin Gilens, Benjamin Page, Larry Bartels and Jason Seawright have demonstrated that U.S. public policy tends to reflect the preferences of the rich, even when these contradict the preferences of most Americans.

Some on the libertarian right have responded to this research by welcoming our new plutocratic overlords. Among these is Bryan Caplan, professor of economics at George Mason University and blogger for EconLog. Even though I disagree with him, Caplan may turn out to be one of the most significant thinkers of our time.

My evidence for this bold claim is a 2012 review by Caplan of a book by Martin Gilens entitled “Affluence and Influence: Economic Inequality and Political Power in America.” In a follow-up paper, Gilens and co-author Benjamin Page recently provided further evidence that American politicians respond more to the preferences of the rich than to those of most voters when the two sets of preferences conflict.

In his original review of “Affluence and Influence,” entitled “Why Is Democracy Tolerable?” Caplan greeted the findings by Gilens with a sigh of relief. Caplan wrote:

Before I studied public opinion, I often wondered, “Why are democracies’ policies so bad?” After I studied public opinion, I started asking myself the opposite question: “Why aren’t democracies’ policies even worse?” The median American is no Nazi, but he is a moderate national socialist–statist to the core on both economic and social policy.

According to Caplan, Gilens had unwittingly provided the answer to the question of why democracies like the U.S. were more libertarian than one would expect, given the “national socialist” leanings of the American people:

Gilens compiles a massive data set of public opinion surveys and subsequent policy outcomes, and reaches a shocking conclusion: Democracy has a strong tendency to simply supply the policies favored by the rich. When the poor, the middle class, and the rich disagree, American democracy largely ignores the poor and the middle class.

Caplan thinks this is a good thing.

In contrast, I find Gilens’ results not only intellectually satisfying, but hopeful. If his results hold up, we know another important reason why policy is less statist than expected: Democracies listen to the relatively libertarian rich far more than they listen to the absolutely statist non-rich. And since I think that statist policy preferences rest on a long list of empirical and normative mistakes, my sincere reaction is to say, “Thank goodness.” Democracy as we know it is bad enough. Democracy that really listened to all the people would be an authoritarian nightmare.

You might be tempted to dismiss Bryan Caplan as just another Koch-funded libertarian hack. But I think he may well be the next great libertarian philosopher. Caplanism may represent the future of that near-oxymoron, libertarian thought.

For most of its post-1945 history, libertarianism has lacked thinkers of its own, and its intellectual deficit frequently has been filled by government-hating businessmen with third-rate minds like Peter Thiel, the fatuous crackpot who founded PayPal, and the appallingly dumb Leonard Read. For a while it looked as though libertarianism had found its Locke or Marx in the late Robert Nozick, following the 1974 publication of “Anarchy, State and Utopia.” But in the 1980s Nozick repudiated his own work: “The libertarian position I once propounded now seems to me seriously inadequate…. There are some things we choose to do together through government in solemn marking of our human solidarity, served by the fact that we do them together in this official fashion [democracy].”

Can Caplan fill the philosophical void left by Nozick’s defection from libertarianism? I think he can. In what follows I will make the case for what might be called Caplanism, recognizing that Caplan himself might not be consistent enough to follow the logic of his own thinking to its conclusions. (Marx claimed he was not a Marxist).

The great contribution of Caplanism to libertarian thought and argument is the observation that democracy, if sufficiently corrupted by the rich, might — just might — be tolerable. Let us call this equivalent of Kant’s Categorical Imperative or the Maximin Principle of John Rawls Caplan’s Tolerability Principle.

That libertarianism is incompatible with democracy is an empirical observation on which libertarians can agree with progressives, centrists and non-libertarian conservatives. After all, in every modern democracy, including the U.S., government tends to account for somewhere between 35 and 50 percent of GDP on such “national socialism” (to use Caplan’s terms) as universal health care, minimum public pensions and public education. As I pointed out some time ago in Salon, there are no libertarian countries.