Marcus Tullius Cicero enjoys a historical reputation as an impressive politician, a profound philosopher, and a master of rhetoric. The circumstances that led to his gruesome demise—his head and hands displayed on spikes in the center of Rome—have made him less likely, however, to appear to posterity as a brilliant strategic mind. Machiavelli expresses a common view in arguing that Cicero’s strategic errors are to blame for his own death, and perhaps even the death of the Roman Republic itself. Machiavelli cites Cicero’s great blunder of empowering Octavian Caesar, whom he hoped to use as a weapon against Mark Antony. When Octavian instead united with Antony, the two abolished forever the Roman Republic and proscribed Cicero. Machiavelli accordingly argues that Cicero should have realized that no good for the Roman Republic could come of another powerful Caesar.
Even a defender of Cicero’s choice to enable Octavian—on the grounds that there were few better options available to Cicero in light of Antony’s threat—would not likely treat him as a great genius of strategy or diplomacy. Cicero had played no significant commanding role in the civil wars that marked the end of the Republic. Nor could he boast of a distinguished military or diplomatic carreer prior to that chaotic period. Cicero had risen from an obscure family to the height of consular power in Rome, through his forensic and rhetorical ability and by forging a link between Rome’s old aristocracy and the equestrian class. Cicero could claim neither conquest of Gaul, nor subjugation of a foreign enemy like Carthage as grounds for considering him an authority on grand strategy.
Despite this, we find in Cicero’s moral and philosophic works a powerful theoretical framework for understanding (and justifying) the strategy and policy of an imperial republic such as Rome. Within this framework are serious thoughts about the relationship between power, interest, and the values of a republican polity. Not only are these thoughts profound and worthy of consideration in their own right, but they proved deeply influential to later thinkers. Importantly, these ideas would ultimately inform the ideological self-image of the Roman Empire.
In both his philosophic works and in his public speeches, Cicero argues that there is an unbreakable link between justice and sound policy. The Roman Republic had grown great not through sheer brute strength, but because its internal institutions and its foreign policy better corresponded to the demands of justice than any other state. In claiming this, Cicero was not naïvely suggesting that divine forces had conspired to reward the moral uprightness of the Romans. Instead, he suggests that the practice of justice internally allowed Rome to marshall far greater military and economic resources than its rivals, while its external practice of justice ensured that Rome enjoyed reliable alliances to advance its interests and guard against threats. Cicero insists that this kind of power does not arise merely from perception—it is not that Rome benefited from falsely seeming just—but rather that the actual practice of justice brought with it tangible strategic rewards.
Cicero also argues that the hegemonic place of Rome in the Mediterranean world gives it both special rights and special obligations in the international realm. Disputes between other states—and even internal disputes within other states—can threaten the peace and order of the Mediterranean world. For Cicero, Rome is entitled to adjudicate such conflicts—or at least it was so entitled, as long as Rome’s power was matched by a commitment to justice. Cicero attributes the chaos and war of the Republic’s last years to the failure of Rome to adhere to the standard that had raised it to power in the first place.
Perhaps most strikingly, Cicero suggests that instead of falling into the temptation of using its power to exploit its neighbors, Rome ought to double down on its original policy of marrying justice to power. He begins to envision Rome as the center of an indefinitely expandable federation of nations (an attitude the Romans had already largely applied to their Italian allies), with citizenship in this republican cosmopolis accessible to all. In other words, Cicero develops the idea of the Roman Republic with a world-historical mission to extend the blessings of just institutions over an indefinitely large empire. Cicero thus appears as perhaps the first thinker to offer a theory of the exceptional republic.
The following is an attempt to sketch the contours of Cicero’s view of how a hegemonic republic ought to wield its power. Cicero’s thought, therefore, ought not to be taken as universally applicable principles of strategy. But that does not mean his argument is of purely historical interest. Cicero understood that it would be entirely possible for another republic to find itself in a similar position to Rome’s—and thus possible for other polities to face the same set of questions and related choices.
The Hegemon’s Prerogative
Cicero was hardly the first to notice that Rome’s positition enabled it to claim certain rights that it denied to other polities. In Caesar’s account of the Gallic Wars, the future dictator recounts the complaint of the Aedui chieftan, Convictolanus: “Why should the Aedui go to Caesar for judgment about their rights and laws, rather than the Romans come to the Aedui?” Convictolanus objects to the non-reciprocal relationship between Rome and those who fall within its sphere of influence. Why may Rome adjudicate internal conflicts of the Gauls, but not vice-versa?
This state of affairs reflected the vast difference in military might between Rome in the middle of the first century BCE and all of its neighbors. From the point of view of pure power, Rome meddled in the Aedui’s affairs because it could. This is the implied answer offered by Caesar to Convictolanus’ objection. Caesar’s career in Gaul reflects a then-standard Roman approach to grand strategy: Rome serves as the local guarantor of order—protecting allies and intervening in the internal politics of other states and tribes to ensure they are governed by leaders friendly to Rome. In particular, Rome supports weaker polities against the stronger in any particular region to prevent the emergence of a serious rival. But theoretically, any state could gain Rome’s protection in return for loyalty to Rome. Cicero says of this state of affairs (before Rome began, in his opinion, abusing its power): “We could more truly have been entitled a protectorate than an empire of the world.”
This universal protectorate model of hegemonic policy seems to have dominated Roman thinking in the late Republic and early Principate, as a way of wielding the largely unchallenged power Rome had by then accumulated. Part of its appeal must have lain in the fact that it required little change in the mindset that had proven so successful in bringing Rome to such a height of power in the first place. From this perspective, Rome’s military might is what makes it truly distinct among its neighbours. This military primacy may in turn be attributable to some other unique feature of the Roman character, such as the virtus of its citizens or soldiers. Or, it may be a product of Rome’s unique constitution and social habits, as Polybius suggests in Book Six of his Histories. But, in any case, the ultimate causes of Rome’s domination must ultimately filter through the proximate cause: its military might. Thus, while this universal protectorate model demands certain concessions to considerations of justice, it does not necessarily imply that Rome’s internal constitution—its laws, values, or institutions—matters significantly in the construction of international policy. In other words, Rome can wield its power over others without considering whether they might resemble Rome in their constitution. Rome’s primary concern is to retain its preponderance of power through the maintainence of peace and the upkeep of alliances—even if that means occasionally stepping in to resolve a civil war or succession dispute in peripheral states. There is no particular set of “Roman values” that need to be respected in waging war or conducting diplomacy; Rome’s foreign policy should simply follow its material interests.
An Exceptional Republic
In the waning years of the Republic, however, Cicero began to articulate a new vision of how Rome ought to think about and wield its vast power. This view retained some points of continuity with the old way of thinking, but it did not accept that viewpoint wholesale. In Cicero’s construal, Rome’s unique military greatness is merely a byproduct of a far more significant uniqueness: its justice. For Cicero, this meant that Rome could be much more than a universal protectorate. It could form the nucleus of a universal confederation, where citizenship could be extended indefinitely so that the principles of justice could be universally secured.
For Cicero, Rome’s power derived more than anything else from the justice of its institutions. Rome offers the living example of the best practical regime. According to Cicero, Rome’s constitution, laws, and values reflect deep wisdom and correspond—albeit imperfectly—to the eternally true natural law. Informed by Platonic and Stoic notions, as well as the Roman legal tradition, Cicero’s account of justice prioritizes the bodily security and freedom of persons, and demands that people have a say in the laws that govern them.
Cicero looks at Rome and sees a mixed regime, with a near-ideal balance between democracy, aristocracy, and monarchy, that gives each of the simple forms of government its due. Thus, “magistrates have enough power, the council of leaders has enough authority, and the people has enough liberty.” Although the primary locus of policy-making (consilium) lies in the aristocratic Senate, Cicero insists that a true res publica actually belongs to its people as a whole: “The commonwealth is the concern of the people (res populi). However, a people is not any collection of human beings gathered in whatever way, but a sizable group allied together by agreement about right and common interest.” Rome reflects the principle that the people have an ownership right in their regime. Following on and flowing from this fundamental right, the people enjoy a number of other privileges that entitle them to a basic level of political participation and strong legal rights that protect their persons and property from arbitrary harm or exploitation. Cicero takes some of these rights, such as the right to vote and the right against arbitrary punishment without due process, to be essential to the justice of the regime and the freedom of the people.
Cicero is not superstitious—he does not believe that Rome enjoys its powerful position because the gods approve of its just behavior. Rather, Cicero believes firmly in the practical utility of goodness. His most famous work, De Officiis, is dedicated to proving the ultimate unity of honestum (the morally upright) and the utile (the useful). For Cicero, injustice always breeds instability—as those treated unjustly will vent their resentment and seek revenge or restitution. Rome’s just institutions ensure that all citizens—even the poorer plebians—have a stake in the political community and enjoy valuable rights and privileges. This means that not only does Rome have less to fear from an uprising from below, but that it can wield the full resources of its society in a way that less justly organized polities around it cannot. Just internal institutions have real practical benefits for power.
Justice in War
Cicero argues that the practice of justice likewise has great benefits in international relations: “The rule of the Roman people maintained itself by benefits, rather than injuries; wars were waged either to defend allies to our own dominion, the Senate was a haven and refuge for kings, peoples, nations.” Wars themselves were fought primarily for defensive purposes: “Our generals sought to gain highest praise by defending fairly and faithfully our provinces and our allies.” Injustice has the opposite effect: Rome’s more recent “outrages against allies” have sparked rebellions and siphoned off strength from Rome’s alliances. Injustice toward allies is ultimately self-defeating as policy. Justice, then, is a part of a prudent national strategic outlook.
One might reasonably object that the actual practice of Rome’s foreign policy little conforms to this rosy picture. Yet, there is some measure of truth to Cicero’s construal. Even during its violent rise to power, Rome generally conducted its foreign policy with at least a patina of morality. The fetial laws—which established the religious and moral basis for going to war—were (usually) scrupulously upheld. Wherever possible, Rome preferred to view itself as waging defensive (and therefore just) wars, either to protect itself or to honor its obligation to protect allies. Even if most of this was pretense, the fact that the Romans preferred to maintain even the pretense—rather than simply avow their expansionist intentions, as the Athenian ambassadors do in Thucydides’ account—suggests that they took the demands of interstate justice at least somewhat seriously.
Cicero sought to encourage such tendencies of the Romans and to discourage the more vicious and shortsightedly self-interested features of Roman foreign policy. He deplored the destruction of the Greek city of Corinth. He rebuked Rome when it failed to honor treaty obligations.
Most significantly, Cicero is one of the first thinkers in the Western tradition to begin to articulate a discrete theory of just war. He argued that recognizing the basic fact of human dignity means that even war does not liberate us from all of our moral obligations to an enemy: “Justice in warfare must be preserved in public affairs.” Cicero’s argument includes the outlines of both in bello and ad bellum elements of just war. With regard to ad bellum, he claims that “wars thus ought to be undertaken only so that we may live in peace without injustice; and once victory is achieved, those among the conquered who were not cruel or brutal should be spared,” even if they surrender after the battering ram had already touched their walls. Wars also ought to be declared formally before conflict commences, according to the fetial laws. As for in bello considerations, as long as your enemy is not waging a war of annihilation against you, you are bound by any oaths you make to the enemy, and you must not engage in underhanded practices like bribery or assassination to achieve your aims.
In all of this, Cicero’s attitude toward war’s place in an overarching national policy reflects his view that the only legitimate purpose of war is the achievement of a just peace. The logic of the rules of warfare reflects an insight that Kant (a close reader of Cicero) would later make explicit: “No state at war with another shall permit such acts of hostility as would make mutual confidence impossible during a time of future peace.” Treachery, assassination, bribery, and the like—all make it impossible for enemies to trust one another when reaching out to make peace, and so Cicero says they ought to be forbidden. Once again, this is not simple altruism made policy—rather, Cicero insists that the nation’s highest true interest is a just peace, and that the failure to follow the rules of just warfare will make it harder (or perhaps impossible) to achieve that goal.
The Universal Commonwealth
Even in his passages outlining how Rome ought to conduct itself in wars with other nations in De Officiis, Cicero hints at an idea for achieving a far more lasting peace. Here and elsewhere in his writings, Cicero suggests that perhaps Rome ought to do more than merely become a still more just and stabilizing citizen of the international order: Rome ought to remake that order entirely. Thinking through his own premises about the nature of justice, Cicero moves toward proposing that Rome use its power to make a thoroughly new global system that would leave the requirements of justice less to chance—and also better serve the interests of Rome.
Although Cicero claims that the only legitimate wars are those carried out for the sake of a just peace, he also explicitly includes “wars for the sake of empire” [bella de imperio] in his enumeration of just causes of war. This would seem contradictory unless the extension of Rome’s power was itself a contributor to just peace. In demanding that Rome always spare conquered enemies who fought honorably, Cicero points out approvingly: “Our forebears even extended citizenship to the Tusculani, the Aequi, the Volsci, the Sabini, and the Hernici.” The defeated peoples mentioned here were not merely conquered, they were incorporated; they were made into legal Romans. Indeed, by Cicero’s time, Rome had extended its citizenship to virtually the whole of Italy.
At this point, the idea of extending Roman citizenship to the non-Italian peoples in Rome’s orbit (with the occasional exception of particular individuals who performed some great service to Rome) was politically unthinkable to Romans. Even broader Italian inclusion had proven sufficiently objectionable to the Romans as to precipitate the Social Wars. Cicero himself never explicitly advocates the indiscriminate extension of citizenship to other peoples. But his thought points strongly in this direction.
Such an extension of citizenship arguably would only further contribute to Rome’s massive superiority of military might—giving it more manpower and resources to draw upon. Indeed, many later writers (Machiavelli, for example) argued that this was in fact the secret to Rome’s great military success. But once again, Cicero sees justice and sound policy as a united concept: The demands of justice are universal, applying to all peoples regardless of culture or circumstance. There ought to be “not one law here, another in Athens, one law now, another in the future, but a single, eternal, unchanging law binding all peoples always.” As the polity whose institutions most closely conformed to this universal standard, Cicero shows how the extension of Rome’s rule offers a way to actualize justice in the world.
One might reasonably object that the conquered peoples themselves could hardly be expected to view their own incorporation within Rome’s polity as a gain for justice. Cicero suggests, however, that they might come to recognize that the benefits of Roman citizenship outweigh its negatives. This was no mere sophistry on Cicero’s part—there was precedent for just such an evolution of outlook. The Social Wars of the previous century had presented the historically anomalous example of one group of people (the Italians) waging a war against Rome because they wanted incorporation into Roman citizenship. The rights of property, a fair trial, and the ballot that Roman citizenship conferred were so valuable that Rome’s Italian allies fought against Rome to get Rome to grant it to them. Once those rights had been won for all (free and male) inhabitants of Italy, they often found that the political participation rights attendant on citizenship were largely inert, as one needed to be present at Rome to make use of them. But the other rights of citizenship, those protecting persons and property from arbitrary harm, could still prove invaluable. Thus, Cicero might reasonably hope that incorporating Rome’s allies and subjects into citizenship could be far preferable for them than to remain in a state of pseudo-independence as protectorates and vassals. Cicero boasts: “From every state there is a road open to [citizenship in] ours…. There is no people in any quarter of the world so constituted… that we are forbidden… to present him with the citizenship of Rome.” This comes quite close to advocating an indefinite expansion and incorporation of peripheral peoples.
In this light, a seemingly unconnected remark of Cicero on the subject of his own birthplace gains new significance: Near the beginning of the second book of De Legibus (On the Laws), Cicero and his interlocutors embark upon a digression. The passage is worth quoting at length:
I believe that both Cato and all those who come from the towns have two fatherlands, one by nature and the other by citizenship. Cato was born at Tusculum but was given Roman citizenship…and had one fatherland by place of birth, the other by law…But of necessity that one takes precedence in our affections whose name ‘commonwealth’ belongs to the entire citizen body, on behalf of which we have an obligation to die, to which we should give ourselves entirely and in which we should place and almost consecrate everything we have… I will never deny that this [Arpinum] is my fatherland, while recognising that the other one is greater and that this one is contained within it… has two citizenships but thinks of them as one citizenship.
On the surface, this is simply a comment about the status of Roman citizens, who, like Cato and Cicero himself, hail from the towns (municipia), and not the city of Rome. But there is a deeper implication to Cicero’s statement. The towns of Arpinum and Tusculum were once independent states themselves. Rome defeated them and eventually brought their inhabitants into Roman citizenship. Cato and Cicero’s ancestors may have died fighting to preserve Arpinum’s independence from Rome, but Cato and Cicero both are now patriotic and successful Romans, full and equal members of Rome’s commonwealth. Cicero offers no reason why this cannot be the model by which Rome absorbs the rest of the known world, simultaneously achieving a just peace and lasting security for itself.
A Framework for Empire
Cicero’s death would coincide with the death of the republic he defended. Ironically, his incomplete vision for a cosmopolitan polity would be taken up by the Principate that established itself on the ruins of that republic. Although politically unspeakable during Cicero’s time, the idea of extending citizenship to all within Rome’s reach would eventually become Roman imperial policy. Over the next few centuries, virtually every male inhabitant of the Mediterranean world would be incorporated as a citizen of Rome. As this happened, many Romans continued to object to the expansion of citizenship, seeing it as a dilution of their privileges. But, in fact, once the right of meaningful political participation had been lost even by the Romans themselves, the remaining slate of rights (such as property and due process) could be extended ever further without any dilution of the same.
A different, sharper moral objection to this policy would be offered later by Tacitus, discussing the situation of Romanizing Britons. He remarks bitterly that the symbols of Roman-ness adopted by the Britons merely served to conceal their subjugation from themselves:
Then, too, came admiration for our style of dress and the common wearing of the toga. Little by little, they were lead to things that conduce to vice: the lounge, the bath, and the elegant dinner party. In their ignorance, all this was called ‘culture,’ when it was really a part of their servitude.
Yet, the dominant later view of the Romans would be expressed (perhaps also cultivated) by Vergil, who gives the following famous image of Rome as a nation on a civilizing mission to the world. In the Aeneid, Vergil’s Anchises tells Aeneas: “Roman, remember by your strength to rule the world’s peoples—for these are to be your arts: to pacify, to impose law, to spare the conquered, and batter down the proud.” This vision of Rome with a world-historical destiny to bring peace and law seems to echo Cicero’s semi-articulated aspiration. Still, because Cicero never explores the practical extrapolation of his principles to the extent to which the Roman Empire would later apply them, he does not examine the potential tradeoff—the erasure of local difference—that Tacitus identifies as the cost of such an approach.
Although Cicero’s model is contingent on Rome preserving its (for Cicero) just republican constitution, he nevertheless can be seen as the intellectual godfather of the later imperial theory of Roman hegemony. In De Re Publica, Cicero’s characters engage in a dialogue about the relationship between justice and empire. One character, Philus, makes the case for injustice by pointing out that a commonwealth “cannot grow without injustice… if an imperial state, a great commonwealth, does not subscribe to that injustice, then it cannot rule over provinces.” On behalf of justice, Laelius replies that subjugation is beneficial for those who cannot obey natural law on their own. “When the right to do injury is taken away from wicked people: the conquered will be better off… do we not see that the best people are given the right to rule by nature herself… why then does the god rule over man, the mind over the body…?”
This idea bears a considerable resemblance to Aristotle’s argument for natural slavery. But in this case, Cicero concentrates on eliminating the possibility of causing harm. Moreover, those subdued are not necessarily subjected to actual slavery—indeed one might even say they have been liberated from their subjugation to injustice. Cicero argues that Rome’s dominion could be (and was, before corruption set in) founded on justice and consent, rather than force. In the famous “Dream of Scipio” at the end of De Re Publica, Cicero offers a vision of the cosmos in which the supreme deity ensures the orderly movement of the celestial orbs. In Scipio’s Dream, the good statesman imitates the deity by guiding and governing his commonwealth. But elsewhere in the same work, the good commonwealth as a whole resembles the god, emulating his role in guiding and organizing the other peoples of the world.
The universality of the principles of justice might seem to imply that no state, no matter how preponderant in power, enjoys special moral rights. After all, if the demands of justice admit no exceptions, then there ought to be no unique moral calculus for a particularly strong state. But the fact that Rome combines a near-ideal (within the bounds of the practical) regime with great military power gives it the opportunity, in Cicero’s view, to play a special role in establishing a truly lasting, because truly just, peace. In other words, the universalistic nature of justice does not necessarily require that rights and responsibilities fall on all equally. The special task of imposing and securing the universal conditions of justice may fall to Rome uniquely. Thus, whether he intended it or not, the famously war-averse Cicero also laid the foundations for a very permissive theory of hegemonic power, one which allows (perhaps even obligates) the hegemonic republic to wage wars of imperial expansion. For, if it is only through the universal subsumption into the good republic that peace, justice, and security can be achieved, unprovoked wars of conquest become instantly justified.
Conclusion: A Moral Doctrine for Hegemony, or Moral Cover for Empire?
It does not take a great imaginative leap for one to notice echoes of Cicero’s arguments in longstanding debates around U.S. foreign policy. The idea of “the indispensable nation,” of wars for democracy, and of the concept of a “leader of the free world” all reflect a similar mode of reasoning to the Ciceronian original. Indeed, not only American, but earlier projects to spread the benefits of civilization have drawn explicitly on Cicero. We can see elements of Cicero’s thought in the ideology of nineteenth century European imperialists, for example. And it is hardly a coincidence that Cicero functioned as “a kind of biblical text” for British colonial officials and public policy makers during the height of the British Empire.
There is thus some obvious merit to a critique of Cicero as an apologist for imperialism. At the same time, to confine our judgement of him in that way would be to miss the great contributions that lie in his thought. Little scholarly attention has been paid to the implications of Roman thought in general for the practice of international relations theory. What little scholarship there is often attempts to locate the Romans somewhere in the realist school—that they accepted power as the ultimate reality of the international sphere. Indeed, in the Western tradition, Greeks and Romans up to the time of Cicero do seem to have been largely realists (to apply the term anachronistically). Thucydides is only the most famous and obvious example. The great Greek moral philosophers, such as Plato and Aristotle, have little to add on the subject.
Cicero is the first major thinker in that tradition to make a serious argument that international power ought to be wielded within a clear moral framework. He rests his claims not on empty normative wishes, but on a sophisticated moral outlook that is also hard-headed, and practical. Cicero offers a compelling argument that national power and national security depend upon just behavior. Thus, even if all one cares about is raw power, pure power-seeking proves myopic: might and right have a complicated and bi-directional relationship. To act purely on the basis of power is both immoral and unwise. On the one hand, vast superiority in might transforms the moral calculus and changes what a state may rightly do. On the other hand, the extent to which a state’s behavior corresponds to justice impacts its real power by the addition or repulsion of potential allies and affects the stability of one’s own internal politics. Considerations of justice, then, are essential even for a purely self-interested hegemon.
Cicero articulates incipiently but profoundly a theory of the dynamic relationship between power and justice. He also proposes a very attractive—one might say seductive—self-image of an exceptional republic that must play an exceptional role in world affairs. This image may provide cover to self-interested projects of empire-building. But it also provides a new framework for thinking about especially hegemonic power that might constrain the hegemon’s action in a way that its weak rival contemporary powers cannot. Cicero’s vision seeks to reconcile republican values with the seemingly un-republican fact of domination (in the international realm). One is thus also entitled to wonder whether the apology of Roman imperialism has been wrong—would later inhabitants of Gaul or Spain really have been better off without the order and civic rights that Roman conquest of their ancestors brought?
Cicero challenges his readers to consider how the internal constitution of a state matters to the appropriate use of its power on the international realm. And as any political theorist worth his salt ought to do, he also prompts us to be attentive to the ways in which a truly pragmatic attitude must in fact consider questions of morality and justice.
Aristotle. The Politics. Translated by Carnes Lord. Chicago: University Of Chicago Press, 1985.
Asmis, Elizabeth. “Cicero on Natural Law and the Laws of the State.” Classical Antiquity 27, no. 1(2008): 1–33.
Atkins, Jed W. Cicero on Politics and the Limits of Reason : The Republic and Laws. Cambridge: Cambridge University Press, 2013.
———.Roman Political Thought. Cambridge University Press, 2018.
Caesar, Gaius Julius. The Gallic War. Trans. H.J. Edwards. Cambridge, MA: Harvard University
Brunt, R. A. Libertas in the Republic in The Fall of the Roman Republic. Oxford: Oxford University Press, 1988.
Cicero, Marcus Tullius. Cicero: De Re Publica. Translated by Clinton W. Keyes. Cambridge, MA: Harvard University Press, 1928.
———.Cicero: De Re Publica. Trans. Clinton W. Keyes. Cambridge, MA: Harvard University Press, 1928.
———.Cicero: The Verrine Orations I: Against Caecilius. Against Verres, Part I; Part II, Books 1-2. Trans. L. H. G. Greenwood. Cambridge, MA: Harvard University Press, 1928.
———. 1913. Cicero: De Officiis. London: W. Heinemann, 1913.
Eckstein, Arthur, Mediterranean Anarchy, Interstate War, and the Rise of Rome. Berkeley: University of California Press, 2007.
Gallagher, Robert L. “Metaphor in Cicero’s ‘De Re Publica.’” The Classical Quarterly 51, no. 2 (2001): 509–19.
Gardner, R. Cicero: Pro Caelio, De Provinciis Consularibus, Pro Balbo. Cambridge, MA: Harvard University Press, 1958.
Hawley, Michael. 2020. “‘The Protectorate of the World’: The Problem of Just Hegemony in Roman Thought.” Polis: The Journal for Ancient Greek and Roman Political Thought 37 no. 1 (Jan. 2020): 44–71.
Harris, William Vernon. War and Imperialism in Republican Rome, 327-70 B.C. Oxford: Clarendon Press, 1985.
Kapust, Daniel. “Tacitus and Political Thought.” A Companion to Tacitus, 504–525.
Machiavelli, Niccolo. Discourses on Livy. Translated by Harvey Mansfield and Nathan Tarcov. Chicago: University of Chicago Press, 1998.
Mehta, Uday Singh. Liberalism and Empire: A Study in Nineteenth-Century British Liberal Thought. Chicago: University of Chicago Press, 1999.
Nicgorski, Walter. Cicero’s Skepticism and His Recovery of Political Philosophy. New York: Springer, 2016.
Nussbaum, Martha C. “Symposium on Cosmopolitanism Duties of Justice, Duties of Material Aid: Cicero’s Problematic Legacy.” Journal of Political Philosophy 8, no.2 (June 2000): 176–206.
Pitts, Jennifer. A Turn to Empire: The Rise of Imperial Liberalism in Britain and France. Princeton, NJ: Princeton University Press, 2009.
Polybius. The Histories, Volume 1: Books 1-2. Translated by W.R. Paton, Revised by F.W. Walbank and Christian Habicht. Cambridge, MA: Harvard University Press, 2010.
Schofield, Malcolm. “Cicero’s Definition of Res Publica.” In Cicero the Philosopher: Twelve Papers, edited by J.G.F. Powell, 63-83. Oxford: Clarendon Press, 1995.
Sherwin-White, A. N. The Roman Citizenship. Oxford: Clarendon Press, 1973.
Tacitus. Agricola. Germania. Dialogue on Oratory. Translated by M. Hutton and W. Peterson. Revised by R. M. Ogilvie, E. H. Warmington, and Michael Winterbottom. Cambridge, MA: Harvard University Press, 1914.
———.Tacitus: Histories, Books IV-V, Annals Books I-III. Translated by Clifford H. Moore. Cambridge, MA: Harvard University Press, 1931.
Thucydides. The Landmark Thucydides. Edited by Robert B. Strassler. New York: Free Press, 1996.
Wood, Neal. Cicero’s Social and Political Thought. Berkeley: University of California Press, 1988.
 Some material for this piece is drawn from my previously published article, Michael Hawley, “‘The Protectorate of the World’: The Problem of Just Hegemon in Roman Thought,” Polis: The Journal for Ancient Greek and Roman Political Thought 37, no. 1 (Jan. 2020), 44-71.
 Polybius, The Histories, Volume 1: Books 1-2, trans. W.R. Paton (Cambridge, MA: Harvard University Press, 2010), 1.2. Polybius, one of the earliest writers to take an interest in Rome’s unique constitution, nevertheless focuses his analysis on explaining what it is that makes the Romans so well-adapted to warfare.
 Rep., 2.57. See also: Cicero, De Legibus, 3.27-28, in Cicero, De Re Publica, De Legibus, Cato Minor de Senectute, Laelius de Amicitia, trans. J.G.F. Powell (Oxford: Oxford University Press, 2006).
 For more on the way in which Cicero’s concept of a res publica denotes collective ownership, see Jed W. Atkins, Cicero on Politics and the Limits of Reason: The Republic and Laws (Cambridge: Cambridge University Press, 2013), 131–33. Also, Neal Wood, Cicero’s Social and Political Thought (Berkeley: University of California Press, 1988); Malcolm Schofield, “Cicero’s Definition of Res Publica,” in Cicero the Philosopher: Twelve Papers, ed. J.G.F. Powell (Oxford: Clarendon Press, 1995), 63-83; Elizabeth Asmis, “Cicero on Natural Law and the Laws of the State,” Classical Antiquity 27, no.1 (2008): 1-33.
 Leg., 3.39; Rep., 2.62; Cicero, Dom., 33; Cicero, De Oratore, 2.199. For De Oratatore: Cicero, On the Orator I-II, trans. H. Rackham and E.W. Sutton (Cambridge, MA: Harvard University Press, 1948). For De Domo Sua: Cicero, The Speeches: Pro Archia Poeta, Post Reditum in Senatu, Post Reditum ad Quirites, De Domo Sua, De Haruspicum Responsis, Pro Plancio, trans. N.H. Watts (Cambridge, MA: Harvard University Press, 1961).
 Centuries later, Machiavelli would likewise attribute Rome’s success to its ability to marshal the power of its lower classes, which it could trust with weapons because their loyalty could be counted upon.
 William V. Harris, War and Imperialism in Republican Rome, 327-70 B.C. (Oxford: Clarendon Press, 1985). Harris, for instance, interprets nearly all Roman rhetoric about defensive warfare as little more than ideological cover for realpolitik aimed at either a domestic or foreign audience (see especially pp. 163-264).
 For instance, Rome’s conquests of both Gaul and Greece were instigated when a weak power allied to Rome appealed to Rome for help against a stronger one. Of course, once the Romans eliminated the threat, they stayed for good.
 De Officiis, 1.38-41. This latter point is far stricter than Rome’s own legal framework for war—an enemy who tried to surrender after the ram had touched the walls could legally be slaughtered. This incentivized early capitulations.
 Rome’s process of actually extending citizenship to the conquered outside of Italia was an extremely slow process that took place in fits and starts throughout much of the period of the Principate.
 Many Romans viewed the extension of citizenship as a dilution of its value. See A.N. Sherwin-White, The Roman Citizenship (Oxford: Clarendon Press, 1973), 96–144; R.A. Brunt, Libertas in the Republic in The Fall of the Roman Republic (Oxford: Oxford University Press, 1988), 93–131.
 Arpinum’s incorporation from the status of an ally into a city with Roman citizenship was peaceful. But, its reduction to the position of an ally in the first place came about only through Rome’s successful conquest of the Volscians; see Sherwin-White, 66.
 Tacitus, Tacitus: Histories, Books IV-V, Annals, Books I-III, trans. Clifford H. Moore (Cambridge, MA: Harvard University Press, 1931), 3.40; Pliny, Panegyricus, 37.2-5. Pliny, Letters and Panegyricus, Books 1-7, trans. Betty Radice (Cambridge, MA: Harvard University Press, 1969).
 Rep., 3.41. For more on the importance of consent to Cicero’s overall conception of political justice, see Walter Nicgorski, Cicero’s Skepticism and His Recovery of Political Philosophy (New York: Springer, 2016) 171–77, and Atkins, 172–74.
 For the interpretation of Scipio’s dream as ‘the rector who rules the state is like the sun who rules the planets,’ see Robert L. Gallagher, “Metaphor in Cicero’s ‘De Re Publica,'” The Classical Quarterly 51, no. 2 (2001), 517.
 Cicero, Cicero: The Verrine Orations I: Against Caecilius. Against Verres, Part I; Part II, Books 1-2, trans. L.H.G. Greenwood (Cambridge, MA: Harvard University Press, 1928), 1.14-15, 2.5-7. Cicero’s attack on Verres illustrates that he does not object to Roman imperium in itself, only its unjust administration. But this very position implies that Cicero believes there are claims of justice that Rome’s administration of empire has a responsibility to uphold.
 Cf. Uday Singh Mehta, Liberalism and Empire: A Study of Nineteenth-Century British Liberal Thought (Chicago: University of Chicago Press, 1999);Jennifer Pitts, A Turn to Empire: The Rise of Imperial Liberalism in Britain and France (Princeton: Princeton University Press, 2009).