It is disconcerting to reflect that Bashar al-Assad’s murder of hundreds of women and children with sarin gas in August constitutes only a small contribution to the overall total of Syrians who have died as a result of his sweaty, desperate cling to power. It is further disconcerting to observe that even that overall total, estimated at around 100,000 dead, is barely enough to elevate his career into the ranks of the truly effective tyrants of recent history. His former neighbor Saddam Hussein is regularly credited with being ultimately responsible for the murder of 300,000 of his own people, a number that does not include Kuwaitis or Iranians. If we look back further into the last century, Assad hasn’t even begun to compete with the agrarian nightmare of the Khmer Rouge or with Hitler, Stalin and Mao.

Not that death tolls are the only important measure of a tyranny, or that we need to go as far back as the last century for examples of tyrants. From the vast human suffering caused by the deranged Kim family in North Korea, to the coldly self-interested hypocrisy of the leaders of "communist" China, to the millenarian theocrats in Iran, it is clear Assad faces stiff competition in his quest to become truly awful. For plenty of good reasons, his actions and his country are at the forefront of the American political conversation right now. But his despotism is not atypical on either the recent or the contemporary global scene. On the contrary: It is normal.

As Waller R. Newell notes at the outset of his deeply ambitious book, Tyranny: A New Interpretation, "We seem to be living through an era in which expectations for freedom and the proliferation of tyranny are intensifying simultaneously." Newell’s aim is to make sense of tyrannical regimes and, by giving an account of tyranny, to shed light on the character of modernity itself. The implications of his argument are unsettling.

At the core of the book is Newell’s assertion that, in the transition from ancient to modern political thought, not only the understanding, but also the very nature of tyranny has changed. Classical authors such as Plato, Aristotle, and Xenophon were deeply concerned with the problem of tyrannical regimes, no doubt due to the fact that for them, as for us, such regimes were very much in evidence.

The rough consensus among these authors was that the tyrant was to be understood as a man with an excess of desire: in classical terms, an excess of eros. He was a man whose lust for honor, sex, and immortality was insatiable, and who was born with the talent and ambition to seize such things. He went ahead and took whole cities for his own possession. Many people, then as now, believed in private that successful tyrants were the happiest men of all: that the profits of injustice were better than the pain of suffering injustice—at least if you could get away with it.

The classical philosophers emphasized the slavishness of the tyrannical life, which despite its superficial appearance of perfect freedom in fact involved being led from moment to moment by one’s darkest passions and being subject to constant fear. Think of Saddam Hussein’s final years in power, sleeping in a different house each night, and wondering constantly which would come first: death at the hands of his own people or death by an American bomb. And while Hussein was not famous for the sort of sybaritic excesses of classical tyrants like Tiberius or Heliogabalus, his sons appeared to be warming up for just such a career before being killed by an American missile in Mosul.

If the excesses of eros formed the basis of the classical diagnosis of tyranny, the nature of eros itself provided the basis for its cure. The therapy prescribed for such cases—most decisively by Plato’s Socrates—was to impose conditions on the desire of young men for temporal goods like sex and public honor, and to encourage them to pursue a balanced life in which their passions would be subject to that faculty that ought naturally to rule: their reason.

Their education would persuade them that the universe was an intelligible and ultimately hospitable place for man, whose nature was perfected by a life guided by a desire not for the false goods of injustice, but by a desire for communion with the Good itself. Plato depicts Socrates putting just such a therapy into effect with a series of interlocutors, most famously the young, beautiful, and ambitious Alcibiades.

In Newell’s view, the pivotal response to this consensus comes from Machiavelli, whose interpretation of tyranny changes not only the conversation about tyranny, but also tyranny’s very nature. The principal debate between Machiavelli and the ancients is not, in this reading, about the nature of politics, but about the nature of the universe.

Though Aristotle and Xenophon might have quibbled with Plato about the precise details of how to respond to the problem of tyranny, they all seemed to be in agreement that the world itself was congenial to man’s nature: that a man of virtue could lead a flourishing life and that his eros, guided by philosophy, could guide him to this happy end.

However, rather than an ordered place that could allow for such a life, Machiavelli presents a world characterized by the principle of fortuna—a universe of chance and meaningless motion. And in such a universe, the ambitious man’s eros cannot be redirected towards a Good that does not exist.

From this insight is born modern tyranny. Faced with an uncongenial universe that cares nothing for him, the ambitious man channels his alienation into a technological project for the mastery of that very universe. Eros is replaced by the Will, and the modern tyrant seeks power not because of his desire for immortality—which he knows is a sucker’s game—but as part of a project to master nature.

Two objections might arise in the mind of the reader considering this characterization of Machiavelli. The first is that if this is modern tyranny, then plenty of modern day tyrants seem still to be ancient. That is, they are better understood not as radical seekers of power for power’s sake and as disciples of a scientifically driven project for the alteration of man’s nature, but as seekers of power for self-gain and self-preservation. Assad, despite his Ba’athism, seems a good example of this, as did Hussein: their oppression is best understood as being in the service of their sect or tribe at the unjust expense of others in their states.

Newell’s response likely would be that political thought is not, as he puts it, "primarily linear." Echoes of the ancient in the modern should surprise us no more than foreshadowing of the modern in the ancient. And while the ancient theory might be able to explain Assad, it cannot explain modernizing despots like Ataturk or utopian madmen like Robespierre, Lenin, or Hitler.

A second objection might be that man’s arrogation of the powers of God, which for Machiavelli is a speculative rather than a complete project, is madness that no man—especially a rational man alienated on Machiavelli’s own terms from the cold, vast, unforgiving universe—actually could believe. In response to this, though, one imagines that if Machiavelli were to walk the earth in the year 2013, he would be struck by what man already can do: fly, destroy the world by nuclear fire, create clones of living beings.

Newell’s book is deeply impressive, and also utterly disconcerting. His argument suggests that tyranny is in the DNA of modernity. Rather than a perversion found in certain ambitious young men, it is at or near the center of what it is to be modern.

Furthermore, Newell suggests that if tyranny is in the DNA of modernity, then a certain failure to take tyranny seriously is in the DNA of liberalism. Hobbes’ narrowing of Machiavelli’s teaching to the politics of the social contract creates no place for the tyrant.

If all men are equal, and among the things that make them equal is that they share as their deepest motivation a fear of violent death, and if they agree to submit to a social contract to protect themselves from that cruel possibility, then why would any man take the risk of being the sovereign? Obviously some men do take that risk, and Hobbes’ omission of their motivation for doing so is a weakness—perhaps intentional—in his account, one that subsequent authors like Locke do not address.

Thus liberalism depends on a vision of human nature that does not account for the cunning will to power of a Machiavellian "real man." And perhaps this accounts for the bizarre fact that, in debating a response to Assad’s murder of his own people, among the principal concerns of American policymakers is whether or not a strike on Syria will make another tyrant—the Ayatollah Khamenei—less willing to give up his dream of nuclear weapons. Liberals cannot understand that tyrants have no interest in their social contract.

And if liberals, whether in the sense of the political center-left, or in the sense of all of us who love the American experiment, cannot take tyranny seriously, then perhaps liberal democracy, far from being the end of history, will prove to be only a curious and temporary byway in history’s course.