THESE REMOTE struggles matter so much, and have done, for so many generations. We are still enthralled by Rome, not merely as a source of extreme human behavior (and it had plenty of that), but as some kind of model, both of what to emulate and what to avoid. Though Goldsworthy does not claim to give us the answer, the book has considerable advantage over most of the other “Antony and Cleopatra” histories on the shelves, providing a very detailed political and military account of the development of the two most important centers of the ancient world after the death of Alexander the Great in 323 BCE.

The modern United States is very, very different from ancient Rome. But it is not only governed from a place called the Capitol; its constitution, despite declaring itself to be democratic, is, as James Madison intended it to be, a variation on the Roman “mixed constitution”—of democracy, aristocracy and monarchy. And like the ancient Roman Republic, although very much despite its better interests and declared intentions, it seems to have acquired a number of overseas commitments frequently decried, usually with more vehemence than reflection, as an “empire.”

Many of the spate of books comparing the United States to Rome (although the number seems to have dropped off since the arrival of the present administration) have done little more than press a rather crude polemical point about the pitfalls of arrogance and overreach, the inherent evils of all empires and consequently of most recent U.S. foreign policy. But the analogies between the United States and first republican, and then imperial, Rome have been part of the ideological history of Thomas Jefferson’s “Empire of Liberty” since its creation. And there is something to be learned from the Roman example, if only because the Roman world lasted for so long, covered so much territory (at its height about 5 million square miles; the continental United States is a little over three and a half million), embraced so many different peoples and underwent so many transformations—from a small, democratic (in the ancient sense of the term) city-state to a worldwide Hellenistic monarchy presided over by a God-Emperor.

One thing the intertwined stories of Antony and Cleopatra, and of Caesar and Cleopatra, may be able to tell us about is the long-term danger inherent in excessive executive power. The republic may have been rotting through corruption and the steady erosion of respect for the law and public office even before Caesar crossed the Rubicon. But it was finally brought to an end first by the struggle between Caesar and Pompey, and then between Antony and Octavian. Both of these, despite the very different personalities involved, had one thing in common: they were both attempts, highly successful in the end, to wrest authority permanently from the Senate. The Roman Empire remained in name, until the end, the empire of the Senate and the People of Rome (SPQR), a phrase carried over from the republican era. The legions continued to fight under the standard which bore the letters SPQR. The title Octavian first took for himself, “princeps,” had strong republican associations (it was the name given to the head member of the Senate); the word “imperator” was a republican term, meaning only he who exercises imperium (“authority”), and was a generic title used by all Roman commanders. Unlike Caesar, Augustus knew about the power of names. To appear republican was good enough to win the hearts and minds of the people. But he also managed to erase all the liberties once enjoyed by both plebeians and patricians alike, so that by the time of his death in 14 CE, the political realities once enshrined in the phrase “the Senate and the People” had become nothing more than a façade.

There were, of course, structural weaknesses in the Roman state which have no obvious parallels today. Despite its great size and wealth, it was a relatively ramshackle affair compared with any modern nation, at least in the developed world. But its greatest flaw, what made Caesar and Antony possible, was what had also made it great: its empire. It is often forgotten that most of what today is thought of as the Roman Empire had been acquired under the republic. Britain, Dacia to the east of the Danube, Arabia, Mesopotamia and Armenia were taken by the emperors (most, with the exception of Britain, by Trajan between 101 and 117 CE). But the full force of Roman expansion had stopped by the first century BCE. It was that empire which had made Caesar and Antony the mightiest of subjects, providing the resources that allowed them to vie for power. Caesar invaded Rome from Gaul; Antony hoped to invade it from Egypt. Without the existence of vast overseas territories and subservient client populations to assist them, the wars both men fought with and against their fellow citizens would not have been possible. Never once did they place the national interest—had they had such a concept—before that of their own.

ALTHOUGH EMPIRES do not necessarily have to be, or to become, some kind of autocracy, most if not all of them in fact have. (Britain, for all Lord Macaulay’s talk in 1833 of its mission to export “European institutions” to India and elsewhere, was really no exception.) The lesson which George W. Bush’s advisers were rumored to have seen in imperial Rome, that in a “unipolar” world—of the kind first-century Europe and Asia arguably were—executive power cannot be allowed to be fettered by quarrelsome allies, was entirely the wrong one. It was not Augustan Rome they should have been looking at, or even the Rome of the public-works-oriented Trajan and the philosopher-king Marcus Aurelius. It was what lay in wait in the third century, when weak and ineffectual emperors, all creatures of the army, followed one another in rapid succession. The miracle about the fall of the Roman Empire, as Edward Gibbon observed, was that it took so long. I do not in fact think that the United States is in any meaningful sense an empire nor, except briefly in 1898 and within the territory of the continental United States, has it ever been. One of the thoughts Goldsworthy’s book might leave us with, however, is that despite all the encouragement it has received, America would do well if, in its own national interest, it never attempts to become one.

Anthony Pagden is a professor of political science and history at the University of California, Los Angeles.

¹ Virgil, Aeneid, 8: 908–912. The translation is by John Dryden.