Democracy in America is not well, but what ails it? According to one diagnosis, the country is suffering from multiple strains of one-man rule — tyranny, fascism, authoritarianism. Variants of the virus originate in the people and their passions. Citizens vote the tyrant into power. Racism, misogyny, or some other affliction of cruelty and fear fuels their votes. Democracy is not just threatened by disease. It is the disease.

This idea, of despotism from the demos, has a distinguished pedigree. Plato and Aristotle thought that all, or nearly all, forms of tyranny arise from the people. The vulgar many oppose the virtuous few, whose ethos of remove is an irritant to the many. Stirred by a demagogue, the people and their leader lay waste to established institutions and elites, upending the rules and norms of the constitutional order. The result is a lawless multitude or lawless ruler, it scarcely matters which, for between a vicious democracy and a violent tyranny lies a narcissism of the smallest difference.

Scholars have shown, however, that tyranny in ancient Greece was less an affair of the masses than the classes, particularly the wealthy and wellborn. Small groups of elites turned recently accumulated surpluses, wrought from newly acquired colonies, into coercive monopolies of political power. Tyranny tracked concentrations of wealth rather than assemblies of the people. The problem was neither rule of the many nor rule of the one. It was rule of the oligarchic few. Far from destroying institutions, Matthew Simonton argues in his authoritative survey, the oligarchs of ancient Greece depended on institutions, both to manage conflict among themselves and to keep the people in a state of powerlessness.

The last two decades have seen a comparable oligarchic turn in the analysis of modern politics. Historians, political scientists, and economists have documented the growing inequality of contemporary capitalist societies. They’ve demonstrated the increasing ability of the wealthiest few — the top tenth of the 1 percent, smaller than a class but larger than a cabal — to use their wealth, and the law, to dictate broad realms of public policy in the United States.

With a few exceptions, that oligarchic turn has not yet steered our understanding of Trumpism. Until now.

Two weeks ago, stirred by a faint rumbling in the discourse, I said that I expected to see, in the coming commentary on Trump 2.0, fewer and fewer mentions of fascism and more and more references to oligarchy. Both accounts suggest a threat to democracy; as the precedent of the Greeks shows, however, they differ on the source of the threat.

This week, Joe Biden used his farewell address to warn against “an oligarchy . . . taking shape in America.” Invoking the age of the robber barons, he didn’t merely speak of growing economic inequality, which is how the Gilded Age is often remembered today. He made the deeper point that an oligarchy of “extreme wealth, power and influence . . . literally threatens our entire democracy, our basic rights and freedoms.” In the coming weeks and months, I expect to see more of these sorts of arguments, which will filter down into the media and from there into the academy.

Here’s another data point to consider. During the first Donald Trump administration, there was a lot of talk comparing Trump to Andrew Jackson, the slaveholder genocidaire. The point of that comparison on the Left — which was goosed up on the Right by Steve Bannon and the presence of Jackson’s portrait in the White House — was to shore up the view of Trump as a fascist or protofascist (which is how Jackson has been retrospectively imagined).

This time around, we’re seeing fewer invocations of the populist rabble-rousing Jackson. Instead, we’re seeing increasing comparisons to the decidedly anti-populist William McKinley. Why? Not only is McKinley actually Trump’s favorite president — a point Paul Heideman explored in a perspicuous column months ago — but he was also the favorite of the oligarchs.

The point of the Jackson precedent is to make Trump a symptom of democracy, a pathology of mass politics. The point of the McKinley precedent is to make Trump, rightly, a problem of our billionaire political economy.