It is a daunting task to write a book on Thucydides and have something new and interesting to say. A formidable group of scholars, including the incomparable Donald Kagan and Clifford Orwin, have written rich analytical studies that have both illuminated and rendered accessible to us moderns the work of the dean of historians. Following in Kagan’s and Orwin’s footsteps, numerous commentators and students have produced what is now a substantial body of scholarship. Yet Mary P. Nichols has succeeded in giving us a study that opens up Thucydides’ work in a refreshing way by focusing her analysis on the theme of freedom. Looking at The History of the Peloponnesian War (431 BCE) through the complex lens of freedom, we gain valuable insight and perspective.

Thucydides and the Pursuit of Freedom is a refutation of the larger thesis that Thucydides is a determinist, a believer in the iron rule of necessity at all levels of human affairs, especially politics. Nichols shows that, although Thucydides acknowledged the ample scope of necessity—the role played in history and especially war by larger forces beyond humans’ control—he also recognized the critical part played by freedom, including the decisions and choices made by men and women in the political world. Students and lovers of liberty will be encouraged.

The book draws out a number of stark warnings that Thucydides’ work contains regarding freedom. It is at the essence of human action. Human beings who try to avoid exercising their freedom by seeking refuge in soothsayers, superstition, or the help of the gods often shortchange the possibilities open to them and wind up more subject than ever to the larger forces of chance, necessity, and the stronger will and intelligence of others.

Freedom is key not just for everyman but for the statesman, and is at the core of great deeds in war and peace. It is central to heroism and the quest for glory in war; also to the energy and creativity implicit in successful statecraft; and also to what we might call high culture and art. It carries the potential for ennobling those who grasp its fullness.

Implicit in Thucydides’ immortal History is his awareness that what made Athens ultimately great was its celebration of freedom. Among all the despotisms crowding ancient history, the centrality of freedom at the heart of Athens’ identity was truly distinctive.

Most novel was that Athenian freedom had an individual and a collective component. Athens celebrated the glory of an individual’s freedom to pursue what we might today call his life project, within the context of serious civic obligations. True, such freedom was not enjoyed by women or the numerous slaves who lived within Athens’ walls, but it was nonetheless a remarkable idea, and one that contained within it the seeds of further expansion down the ages to include other human beings. To this day, the history of individual freedom in the world traces to Athens, for the idea was utterly alien to the contemporaneous and highly sophisticated civilizations of ancient Egypt, Assyria, Babylon, Persia, and China.

The collective component of freedom, which Athens both celebrated and violated in its behavior toward other city-states, was the notion that political communities had the right to be free and independent of the dictates of alien communities. A key dimension of freedom was the right of a city-state to nurture and protect within its walls a particular way of life and culture that might not be shared by others. And this kind of freedom, too, stood out in the ancient world, where uniformity, homogeneity, and centralization were prized.

To the extent that the Western tradition, as modulated through the Renaissance and the Enlightenment, has differentiated itself from Chinese civilization, for example, or that of Islam, by placing freedom at the heart of the highest values in politics, culture, and the life of the individual, Thucydides has been one of the key contributors to that legacy. But Nichols helps us to see that there was also, for Thucydides, a dark side to freedom that human beings must keep before them. The greatest nemesis of freedom is its own tendency to excess, to overreaching.

Individually, great leaders and commanders were prone to hubris, prone to discount the role of chance in their success and to exaggerate unnaturally their abilities and luck. They tended to be blind to their own arrogance, pride, and greed, and unwilling to place themselves in the shoes of their adversaries with some minimal empathy. The frequent result: miscalculating their foes’ true strength, force of will, or intelligence, with ruinous consequences for themselves and their city-state.

At the level of communities, those peoples who prospered and grew strong by cherishing their freedom and using it to good advantage slid into empire. They ended up trampling the freedom of other city-states. The Athenian speech at Melos in 416 BCE sounded little different than that of the Persian Great-King attempting to subdue the Greeks several decades earlier.

Nichols develops her analysis by juxtaposing, not abstract ideas or events, but the leading characters in Thucydides’ historical drama: the human beings whose choices illuminate for us the scope and nature of freedom. Besides the historian himself, speaking in his own voice and in the voice of others, she gives us Themistocles, Pericles, Cleon, Diodotus, Brassidas, Nicias, and Alcibiades. All along the way, she reminds us of the double-edged nature of freedom: through freedom, human beings and their political communities create higher forms of political and cultural life in which they find much meaning and fulfillment, but through freedom they also make fateful choices that often destroy the very achievements they have worked so hard to build.

For the author, there is no alternative to freedom as an inescapable element of a full political life for a people and a city-state. In her analysis, Thucydides falls squarely in the center of the Greek tradition that posits freedom as one of the defining, and often tragic, qualities that differentiate human beings from other creatures. Moreover, like his fellow Greeks, Thucydides loved freedom and believed that, at least with regard to the Greeks of his time, most human beings would rather enjoy freedom than not.

The Athenian leader Pericles exemplifies as much as anyone else Thucydides’ understanding of freedom and its complexities. Under Pericles’ leadership, Athens reached the peak of its power, prosperity, and artistic glory. But Pericles understood that Athens’ power rested on its possession of an empire, and that it simply could not let go of that empire without at the same time enhancing the power of its rivals, which included both the Persians and the Spartans and their allies.

Pericles was aware that, in order to be a great, powerful polis, Athens depended on suppressing the freedom of other city-states. The Athenian way of life, centered as it was on its citizens’ liberty to pursue their individual life project, depended in some ways on its capacity to extract from weaker city-states revenues, military contributions, and political commitments that diminished the subordinate states’ freedom. Although Pericles proclaimed the freedom of the individual and the polis to make choices that would render them free and glorious for posterity, his actions as a statesman showed that to a large extent he was imprisoned within the logic of empire. On the basis of that logic, and believing that it gave him no other choice, he prodded Athens into a calamitous war with Sparta. Although in reality Pericles was free not to go to war—and the choice of peace might have been wiser—he came to believe that he really had no such alternative.

Throughout this book we see Thucydides’ understanding that, even though many people see war as an agent of human liberation, and a door to many choices of power, in reality war imprisons human beings and their cities in the increasingly tight grip of necessity. In many ways, war is the ultimate enemy of human freedom. During war, the demands of reason, morality, and prudence essential to shaping the political discourse and the moral and political order give way to the unlimited struggle for power and survival, and human beings fall under the spell of irrational emotions, extremism, and the passions. The excesses of the Corcyrean revolution, Sparta’s harsh treatment of Plataea, and Athens’ horrific punishment of the Melians illustrate this perverse dynamic. Even the supreme calculator and prudent ruler, Pericles, is unable to control war: the unexpected plague, the hardy Spartans, and the impatient Athenian people themselves, combined to upend his carefully crafted military strategy.

Nichols skillfully uses two of Thucydides’ powerful contrasts between individuals to illuminate deeply the contours of freedom in human action. One is the juxtaposition of the immensely popular demagogue and political leader Cleon with his antagonist in the assembly, Diodotus, as the two debated the fate of the rebellious Mytilineans.

Cleon was the democratic politician at his worst, appealing to the fears and lowest motives of his political base. He was also a persuasive orator. He wanted to put all the Mytilineans to death for their revolt against Athens. His antagonist Diodotus understood that an appeal to pure morality as a justification for doing the right thing would fall flat in the assembly. So, he used rhetoric to argue that forgiving the Mytilineans would be in Athens’ self-interest. He succeeded in persuading the assembly. For Cleon, as for the Athenian speakers at Melos a few years later, freedom was the freedom of the strong to rule over the weak, even if it meant tyranny or inhumanity. Diodotus, on the other hand, saw that there are always choices in politics, and that human beings can exercise their freedom to blend the expedient with the moral, thereby producing outcomes that are better not only for oneself but also for one’s enemies. Nichols effectively shows that Thucydides was on the side of Diodotus, not Cleon.

The latter part of Thucydides’ magnificent history is dominated by the contrast between two powerful figures, Alcibiades and Nicias, whose fateful choices doomed Athens to defeat. Alcibiades was a protean figure bound by no limits to his freedom or his ego. He was bold and visionary, but lacking in restraint. He worked the people into a fever pitch with his ambitious scheme to conquer Sicily and beyond. When the people turned against him, he went over to the Spartan side. Nicias, on the other hand, was cautious and conservative, but too much so. When the Athenian expedition to Sicily started to collapse, he failed to act with the requisite decisiveness and turned to soothsayers (the ultimate denial of human freedom) for an indication of what he should do. By thus dithering, he lost precious time he could have used to retreat, and his army was trapped and destroyed.

Thucydides shows us the flaws of these two great men, by walking a fine line between them that suggests how each has something to teach us. Alcibiades’ concept of freedom needed the restraints of moderation and deliberation for it to lead to lasting good for Athens. Nicias was too cautious and conventional to understand the possibilities that freedom opens up to human action in even the worst of circumstances.

Never in any crude or overly direct fashion, Nichols invites us, as we read Thucydides, to cast a side glance at our contemporary American polity in light of Thucydides’ reflections on freedom. Democratic polities are inherently unstable because they have difficulty restraining freedom’s excesses and steering a course of moderation. Democratic political systems also produce their ample share of Cleons and Alcibiadeses—highly ambitious demagogues who have no hesitation in appealing to the people’s basest instincts and worst passions, or to carry the people away in fevered visions of faraway victories that will flatter the people’s ego and sense of exceptional good fortune. Counteracting these demagogues is not easy. A passive Nicias will not do, and Diodotuses are rare.

Equally important to us as to Thucydides are the two dimensions Nichols explores: domestic freedom—the freedom of the citizens of a polis to pursue their way of life as they see fit—and the outer dimension—the freedom of a people to guard and nurture its commonly held political, social, and cultural values as a peculiar system of government, regime, or society.

Today’s United States insists that every society in the world naturally aspires to a democratic system like its own and should move in the direction of having one. But it is clear that Thucydides did not believe that democracy works best for everyone. In The History of the Peloponnesian War he recognizes the freedom of different societies to have their own regimes, and the importance of not allowing differences over regimes to push states into wars they do not want. This, too, is a major dimension of freedom, and one to which Thucydides points us with refreshing relevance.

What we are left with in the end is the inescapability of freedom, but also the need to moderate it with other qualities of character that Aristotle would later identify as the elements of prudence or practical wisdom: the effort to see things as they really are rather than as we want them to be; deliberation; good sense; generosity; magnanimity; and some empathy. Within the context of these moderating qualities, freedom becomes a powerful enabler of human achievements in the service of a broader community within which individuals and city-states can flourish.

As Diodotus showed in the Mytilenean debate, it is possible to be both good to others and good to oneself, to serve one’s rational self-interest without crushing the dictates of common morality and humanity. This, too, is part of the way the world really is, and Nichols deftly shows us that Thucydides’ realism, far from being a steppingstone to nihilism, is an invitation to a hard prudence that can ultimately succeed in alleviating the harsher contours of human existence precisely because it is grounded in the possibilities open to human freedom in a world under the heavy weight of necessity and human passions.