Ancient Rome and the Constitution, Part IV: Historical and Constitutional Lessons the Founders Learned From the Romans

The founding generation drew lessons from Roman history when fashioning the structure of the Constitution.

A bust of Cicero in Rome. Andrea Izzotti/Shutterstock

Commentary

This is the fourth installment in the “Ancient Rome and the Constitution” series. The first installment depicted the central place of Roman writings in the Founding-Era educational curriculum and the popularity of Roman references among the general public. The second installment thumbnailed Roman history and identified the writers with major influence on the Founders’ political thought. The third described the process by which the Constitution was proposed and adopted and showed how Roman history offered moral lessons to the Founders.

This installment discusses some of the lessons that the founding generation drew from Roman history when fashioning the structure of the Constitution.

General Principles and Mixed Government

Before getting into the details of writing a constitution, Americans had to consider their goals. This entailed identifying the basic principles that the Constitution would reflect. John Adams was serving as a diplomat in Europe during most of the constitutional debates. While there, he wrote an encyclopedia of republican governments: “A Defence of the Constitutions of the United States.” (The “Constitutions” referred to were those then in force in the states.) The first volume was issued in early 1787 and was cited frequently during the constitutional debates.

In that volume, Adams relied on Cicero for some basic political propositions, including the following:

• Law is built on justice; where there is no justice, there is no law.
• A nation is not just a mass of individuals but an association based on consent.
• The best constitution mixes elements of monarchy, aristocracy, and democracy.
• Unmixed governments degenerate into corrupt forms, particularly into tyranny. A tyranny is not a true republic because a republic is the property of the people, while in a tyranny, everything belongs to the ruler.

The points about mixed and unmixed government were particularly important to the constitution-makers. Aristotle had divided uncorrupted constitutions into monarchies, aristocracies, and democracies. But he observed that each uncorrupted form tends to deteriorate into a corresponding corrupt form. Monarchies degenerate into tyrannies, aristocracies into oligarchies, and democracies into mob rule.

When explaining the Roman Republic’s success to his fellow Greeks, Polybius emphasized Rome’s unwritten constitution as a major contributor to that success. He pointed out that its government was not a monarchy, an aristocracy, or a democracy but a mixture of all three: The republic’s popular assemblies were (somewhat, but not entirely) democratic, the Senate was (somewhat, but not entirely) aristocratic, and the consuls shared the power formerly exercised by kings. Each element checked the other, preventing degeneration into corrupt forms.

The following chart depicts a simplified version of the government of the Roman Republic. It shows three of the four popular assemblies, omitting one that served purely religious purposes. The chart suggests how the different branches checked each other.

Note that under the republic, the Senate was primarily an executive, rather than a legislative, body. During the early empire, it took on more legislative functions.

Federalism

The Constitution’s greatest contribution to political theory may have been its system of federalism, under which the people divided sovereignty, granting some to the central government and the rest to the states. While developing this concept, the Founders consulted a number of federal models, including confederacies of city-states in ancient Greece and more recent confederacies in Switzerland and the Netherlands. The Founders also took into account the British Empire’s working arrangement before 1763, in which the central government in London controlled foreign affairs, the post office, and commerce with foreign nations and among units of the empire, while the colonies otherwise governed themselves.

Among these models, the pre-1763 colonial arrangement was probably the most influential among the Founders. However, they also seriously considered the Greek confederacies. Their information on those confederacies derived primarily from Polybius and Plutarch.

Polybius and Plutarch were the sources of John Adams’s discussion of Greek confederacies in his treatise on republican governments. They likewise were sources for James Madison’s famous pre-convention research notes, “Of Ancient and Modern Confederacies.” Madison deployed his knowledge of the subject in Federalist No. 18, where he compared the Greek Amphictyonic Council to the United States under the Articles of Confederation:

“The powers [of the Council], like those of the present Congress, were administered by deputies appointed wholly by the cities in their political capacities; and exercised over them in the same capacities. Hence the weakness, the disorders, and finally the destruction of the confederacy. The more powerful members, instead of being kept in awe and subordination, tyrannized successively over all the rest.”

Madison concluded that the new federal government should act primarily on individuals, not on the states. By contrast, Madison’s then-rival James Monroe—the future president, but at the time an Antifederalist—relied on Polybius’ account of the Greek Achaean League to argue that the Articles of Confederation, if amended somewhat, would be adequate for American needs.

Another lesson drawn from Polybius and Plutarch was that if a confederation has some members that are monarchies and others that are republics, the monarchies will try to undermine the republics. This lesson led to the Constitution’s Guarantee Clause (Article IV, Section 4), by which the United States guarantees to every state a republican form of government.

In Federalist No. 34, Alexander Hamilton drew on his knowledge of the Roman constitution to answer opponents’ claims that sovereignty could not be divided:

“To argue ... that this co-ordinate authority cannot exist, is to set up supposition and theory against fact and reality .... It is well known that in the Roman republic the legislative authority, in the last resort, resided for ages in two [actually four!—editor] different political bodies not as branches of the same legislature, but as distinct and independent legislatures. ... It will be readily understood that I allude to the COMITIA CENTURIATA and the COMITIA TRIBUTA. ... These two legislatures coexisted for ages, and the Roman republic attained to the utmost height of human greatness.”

Other Constitutional Lessons

During the course of the constitutional debates, participants looked to Roman sources for other lessons as well. Thus, a Virginia Federalist cited Cicero in support of the Constitution’s grant of the pardon power to the president and its bans on state and federal ex post facto laws (retroactive criminal laws).

In Federalist No. 63, Madison used the Roman example to underscore the need for a federal Senate.

“History informs us,” he wrote, “of no long-lived republic which had not a senate.”

And Hamilton, writing in Federalist No. 70, emphasized the need for a single president rather than an executive council or other plural executive:

“Every man the least conversant in Roman history, knows how often that republic was obliged to take refuge in the absolute power of a single man, under the formidable title of Dictator. ... A feeble Executive implies a feeble execution of the government. A feeble execution is but another phrase for a bad execution; and a government ill executed, whatever it may be in theory, must be, in practice, a bad government.”

On the other hand, an opponent, writing under the name of “Caveto” (Latin for “Be ye warned!”), cited Tacitus’s “Histories” on the Risks of a Unitary Executive:

“They who would put their country under such a form of government, and think thereby to render its condition more safe and easy, must suppose that none but good Princes shall be upon the throne, which did not happen to the Romans, when they had the choosing of their own masters—They were often mistaken in their choice; some had good inclinations, but were corrupted by those about them. In others, the seeds of vice and cruelty lay undiscovered as in Tiberius [the emperor immediately succeeding Augustus]; others’ nature had formed well enough, but so much power turned their heads, and made them worse—Solusque Vespasianus Omnium ante se Principum in melius mutatus est.” (“Compared with all the emperors before him, only Vespasian turned out for the better.”)

Robert G. Natelson, a former constitutional law professor who is senior fellow in constitutional jurisprudence at the Independence Institute in Denver, authored “The Original Constitution” (4th ed., 2025) and is a contributor to the Heritage Foundation’s “Heritage Guide to the Constitution.” He also authored the scholarly article “Virgil and the Constitution,” whose publication is pending in Regent University Law Review.

Views expressed in this article are opinions of the author and do not necessarily reflect the views of The Epoch Times.