The Spirit of the Laws is one of the great Enlightenment-era documents of political philosophy and comparative law. Written and researched by the Baron of Montesquieu over the course of decades, The Spirit of the Laws is the culmination of a lifetime of study in civics, politics, geography, history, and classics. Published in 1748, defended in a separate treatise in 1750, and updated again in 1757, The Spirit of the Laws underwent significant developments before it reached its final form. It is both a product of its time and a significantly influential work on Western political thought in continental Europe and the Americas.

The author, Charles-Louis de Secondat Baron de Montesquieu (now known simply as Montesquieu), was a French nobleman who first rose to literary fame with the publication of the Persian Letters, a witty account of fictional correspondence between two Persian men observing the customs of 18th-century Europe. He was educated in the law and served in Parlement (an appellate court of the French monarchy) as a jurist and judge where he oversaw criminal proceedings for over a decade. He then went on an extended expedition abroad, staying in several major European centers. During this trip, he stayed in England for two years and gained great admiration for their political system, a sentiment expressed throughout The Spirit of the Laws. Upon returning to France, Montesquieu engaged in a protracted political and cultural study that eventually led to De l’espirit des loix, or, in English, The Spirit of the Laws.

Originally published in French, The Spirit of the Laws was translated into English in 1750. Just a year later, the Roman Catholic Church added it to their index of banned books (possibly due to the treatise assigning the clergy no political power, implicitly affirming a separation of church and state). In later generations, Montesquieu’s work was extremely influential in colonial America. Thomas Jefferson even translated a commentary on the work. The Spirit of the Laws is one of the most cited texts amongst the leaders of the American Revolutionary War and the founding fathers of the United States. Jefferson’s anti-federalism, in particular, was informed by Montesquieu’s account of republican virtue. Montesquieu is also an early theorizer of the threefold separation of powers and its corresponding system of checks and balances, a doctrine foundational to the American political system.

This study guide references the Cambridge edition of The Spirit of the Laws, translated and edited by Anne. M. Cohler, Basia Carolyn Miller, and Harold Samuel Stone.

Summary

The Spirit of the Laws is divided into six parts. Though all six parts are extensive and detailed, Part 1 is the most influential and rich in political philosophy. In it, Montesquieu outlines a series of important distinctions employed throughout the remainder of the treatise.

Montesquieu notes the diverse kinds of laws. Though there are natural and divine laws, his concern is with positive law, the law created by people in civil societies. He also presents a theory of rights hinging on the crucial difference between the rights of nations, political rights, and civil rights: The rights of nations are the rights that nations have in exerting their power internationally; The “political right” deals with the government’s relationship to its citizens; and the “civil right” governs citizens’ relations to one another. Keenly aware how often these rights are confused, the author provides numerous examples of this confusion leading to social ills. Any nation’s “spirit of the laws” arises from the general relationship between the forms of rights as they interplay with the cultural values, religions, climates, geographies, virtues, and vices of the people. This “spirit,” which is the true subject of Montesquieu’s inquiry, emerges from the laws’ relations with the whole physical and social world of a people. It is this spirit, in all its nuance and specificity, that should guide all governance.

For Montesquieu, there are three fundamental types of government, and he structures the entire book around these three types: republics (of which there are both democracies and aristocracies), monarchies, and despotic regimes. Though the “spirit” is particular to the society, these three forms of government tend toward one of three overarching spiritual positions, or principles of action: The republic is governed by virtue; the monarchy, by honor; the despotic regime, by fear. In each case, the prudent legislator(s) will reinforce that principle in the citizenry. The virtue of a republic, according to Montesquieu, is not moral virtue per se but political virtue. Therefore, the good republic, for example, seeks an engaged and civically minded citizenry.

While these three types of government correspond to spiritual principles, they are simultaneously defined by their literal political infrastructure. Each can be identified by two defining features: how many individuals govern and whether they do so with the rule of law. Republics are self-governed by the multitude and enforce, more or less equally, the rule of law. Republics are democratic when all governing subjects are citizens; they are aristocratic when only a fraction of the populous has sovereignty. Monarchy entails one individual who governs according to established law. Despotism is the rule of one who is not bound by law. Montesquieu’s favorite example of a republic is Rome. Montesquieu often cites France as a powerful, functional monarchy. Asian nations, especially Japan and China, are frequently cited as despotic.

Montesquieu writes in favor of “moderate governments,” or social regimes that institute political liberty. For Montesquieu, political liberty does not entail the freedom to act as one wants; rather, liberty is the freedom to act virtuously. Republics are the form of government most well constituted to political liberty. It is in this context that Montesquieu constructs his tripartite theory of moderate government. This theory relies on the separation of three branches of government: “legislative power, executive power over the things depending on the right of nations, and executive power over the things depending on civil rights” (156). These three powers should be housed in three separate branches of government (and they correspond to the three branches of government operative in the United States): the legislative, the executive, and the judicial branches. The power to make law is granted to the legislature. Internationally, this law is executed by the executive branch, which acts according to the “right of nations.” Criminal and civil law is executed by the judicial branch.

The remainder of the treatise analyzes modern and classical governments from across the world (primarily Europe and Asia). For Montesquieu, a civilization’s mores enormously impact the nature of the government. The mores include the customs and social practices that define a way of life. The mores motivate both the behavior and psychology of political subjects and contribute to the general spirit of a people, with which the spirit of the laws should be in accord. Social mores and positive law are in reciprocally causal relationship: Good laws work in tandem with strong mores to reinforce the spirit of a people, who then write more good laws.

Mores and laws are also impacted by numerous contingent factors, some of which Montesquieu discusses at great length. For instance, Montesquieu routinely cites regional climate and geography to explain divergent human characteristics, claiming that warmer climates make for lazier people, etc. Other factors include geography, history, regional rivalries, and religious institutions. For Montesquieu, a people’s “general spirit” issues from this confluence of influences. Determining prudent governance is highly relative to this general spirit and requires strict attention to all these details. While Montesquieu finds despotic regimes distasteful, he does not claim that despotism should not exist; given the particular spirit and scope of a regime, even the despot has their proper place.

Although many aspects of his work are forward-thinking, Montesquieu was not immune to many of the racial and patriarchal prejudices of his milieu. Like many Enlightenment era philosophers, he believed in universal equality among men, and in most cases, he was strongly opposed to slavery for this reason; in Part 3, he presents a famously lacerating satire of popular justifications for chattel slavery. Still, he asserts that there are some situations in which slavery may be “more bearable” than in others—e.g., within a despotic state where the citizenry is already held under a political slavery to the despot, and so civil slavery within this environment would supposedly be less intolerable. Additionally, he surmises that inhabitants of nations in warmer climates (decidedly farther south than Europe) are of inferior character due to the warm climate’s softening influence. His attitude is also resolutely patriarchal and, occasionally, explicitly misogynistic. Since many of these opinions appear only in the later parts of the book, and because the majority of Montesquieu’s most influential and philosophical ideas are expounded in the earlier parts, this guide’s chapter summaries will focus most heavily on Parts 1 and 2. Though the entire book is treated, the key themes and terms are almost exclusively provided in the first two books of The Spirit of the Laws.