The Supreme Court has developed an increasingly pronounced reliance on Charles-Louis de Secondat, Baron de La Brède et de Montesquieu, as an authoritative voice on American constitutional structure. But the Montesquieu who appears in the United States Reports is not the complex, empirical sociologist who authored The Spirit of Laws in 1748.1 This Note argues that neither of the Court’s principal approaches to separation of powers — formalism and functionalism — fully engages with the intellectual tradition each claims to inherit from Montesquieu.2
The formalist approach treats Montesquieu’s maxims as categorical rules demanding firm barriers between the three branches of government3 when he never argued for such an approach. The functionalist approach, though closer to the mark,4 fails to grapple with two features of constitutional development that make Montesquieu’s specific prescriptions structurally inapt.5 First, his separation of powers was built atop Polybius’s theory of mixed government, which balanced distinct social classes through distinct institutions.6 The American Constitution has no formal mechanism for class representation. Second, Montesquieu envisioned a judiciary that was “in some measure next to nothing”7 — a set of temporary factfinding panels, not the permanent, powerful institution now policing the boundaries of the other branches and adjudicating public law disputes against the government itself.8 Both sides invoke Montesquieu; neither has undertaken the sustained engagement with The Spirit of Laws needed to illuminate how his thought bears on contemporary structural questions.
Figure 1: Number of Cases Citingor Quoting Montesquieu
These points carry increasing practical significance. The Court’s invocations of Montesquieu have grown more frequent and consequential,9 even as constitutional structure has drifted further from the arrangements he described.10 Recovering the historical Montesquieu also carries particular significance for originalist methodology, which claims to reconstruct the Founders’ intellectual world.11 If originalism demands fidelity to Founding-era understandings, it requires grappling with the thinker the Founders most frequently consulted12 — and with what he actually wrote, not the simplified maxims modern doctrine has substituted for his thought.
This Note proceeds in four parts. Part I demonstrates that Montesquieu was an empiricist in the Aristotelian tradition, not a formalist — recovering his inductive methodology and its implications for constitutional interpretation. Part II identifies the structural transformations rendering his specific prescriptions inapplicable: the disappearance of class-based bicameralism, the transformation of judicial power, and the emergence of public law jurisdiction nowhere contemplated in his framework. Part III argues that Montesquieu’s actual views counsel against the very formalism now practiced in his name and may support institutional arrangements — such as independent agencies — that formalists attack. Part IV considers why understanding Montesquieu matters for originalist methodology. A conclusion follows.
I.
The Court’s separation-of-powers doctrine is organized around a familiar (albeit contested13) axis: formalism versus functionalism.14 Both sides invoke Montesquieu, but in ways revealing more about the Court’s own commitments than his.
A. The Formalist Montesquieu
Formalist opinions deploy Montesquieu as a source of categorical rules.15 The method is remarkably consistent: A passage from Book XI, Chapter 6, usually filtered through Hamilton’s Federalist No. 78 or Madison’s Federalist No. 47, is applied as though it were a constitutional command. Two passages comprise the formalist canon’s core. The first warns that concentrating legislative and executive authority in one set of hands generates tyranny — the same body making the law will enforce it oppressively.16 The second extends the principle to judicial power: When judges also legislate or execute laws, citizens face the arbitrary will of those adjudicating their claims.17 These passages recur across a line of cases stretching from Myers v. United States,18 through Clinton v. City of New York,19 to SEC v. Jarkesy,20 always deployed as proof that the Constitution mandates strict separation betwixt the branches.21
But as Madison demonstrated in Federalist No. 47 — which hailed “the celebrated Montesquieu” as “[t]he oracle who is always consulted and cited on this subject”22 — this reading strips Montesquieu’s observations from their context. Madison explained that Montesquieu never intended the departments “to have no partial agency in, or no control over, the acts of each other.”23 To conclude as much, Madison went to the source: He examined the English constitution, where the branches Montesquieu praised were substantially intermingled.24 The King, acting “alone,” promulgated legislation through treatymaking; the House of Lords exercised legislative as well as judicial power via appellate review “in all” cases besides impeachment (where it held original jurisdiction); and judges were “so far connected with the legislative” branch that they “often” participated in legislative “deliberations” alongside lawmakers.25 Montesquieu nonetheless pronounced this arrangement the constitution of liberty.26 Madison’s conclusion was straightforward: Montesquieu’s maxim prohibits only vesting “the whole power of one department” in hands already holding “the whole power of another”27 — not partial overlap nor the kind of functional sharing formalists now find intolerable.28
Indeed, even leading scholars of classical legal theory like Professor Adrian Vermeule have acknowledged Montesquieu’s discussion of executive power is ambiguous on the questions most important to executive unitarians — his equation of one branch of executive power with judging, together with uncertainty about whether domestic regulatory functions fall within his conception of executive authority, leaves the text genuinely indeterminate on the questions formalists treat it as resolving.29 If the canonical passages cannot answer even the threshold question of what Montesquieu meant by executive power, extracting from it a categorical mandate for particular institutional arrangements overreads the text.
B. The Functionalist Reading
Functionalist opinions, by contrast, hew closer to Montesquieu’s text.30 They acknowledge strict separation is neither possible nor desirable, reading Montesquieu’s warnings as concerns about concentrated power, not as mandates for categorical interbranch boundaries. Take Loving v. United States,31 for instance. There, the Court rejected a nondelegation challenge partly because “a ‘hermetic sealing off of the three branches of Government from one another would preclude the establishment of a Nation capable of governing itself effectively’”32 — a view Montesquieu had introduced through the Framers.33 Other examples abound. Justice Blackmun upheld the Sentencing Commission in Mistretta v. United States,34 while “recogniz[ing] the continuing vitality of Montesquieu’s admonition” against commingling whole powers, reasoning the Constitution doesn’t require airtight compartmentalization.35 In Nixon v. Administrator of General Services,36 the Court quoted Madison’s qualification approvingly.37 Justice White’s dissent in INS v. Chadha38 concluded (as Madison did) that “the oracle of the separation doctrine, Montesquieu,”39 never meant branches should “have no partial agency in, or control over the acts of each other.”40
Montesquieu’s own words confirm the functionalist instinct. He recognized that governmental powers, though distinct, “have need of a regulating power to moderate them”41 and are “forced to move . . . in concert.”42 The judicial power — which, “in general . . . ought not to be united with any part of the legislative” — should nonetheless be subjected, “in some cases,” to legislative review when specific applications of “the law . . . might” prove “too severe.”43 And in cases where an individual “entrusted with the administration of public affairs may infringe the rights of the people, and be guilty of crimes,” Montesquieu also saw fit for the legislature to criminally convict the accused.44
Indeed, Montesquieu “never used the word separation.”45 He instead spoke of a “certain distribution” of powers, a phrase suggesting calibration and balance, not hermetic division.46 On his view, “two goals” were served by distributing rather than “strictly separat[ing]” the government’s three powers: first, “the ability” for power to effectively “check power,” and second, “by means of this very check, it permitted moderation in the government.”47 This is a vision of coordinate powers in dynamic interaction, not sealed compartments with categorical boundaries.48
C. The Aristotelian Methodology
The formalism-functionalism debate has obscured something more fundamental about Montesquieu’s intellectual project: its Aristotelian character. Understanding this methodology matters not only because it reveals what Montesquieu actually argued but because it bears directly on how his thought should inform constitutional interpretation. The Spirit of Laws was greeted upon publication “as the first systematic treatise on politics since Aristotle”49 — a comparison as methodologically precise as it was flattering. As Professor Céline Spector has demonstrated, Montesquieu’s approach owed a specific debt to Aristotle’s Politics: Both works catalogue and compare actually existing governments in lieu of deriving institutions from abstract premises.50
The parallel runs deep. Aristotle collected and analyzed 158 Greek city-state constitutions;51 Montesquieu ranged across Europe, Asia, and the Americas.52 Aristotle distinguished constitutional forms by their internal logic and social conditions;53 Montesquieu did the same, adding “the quality of [a nation’s] soil, . . . the principal occupation of the natives, whether husbandmen, huntsmen, or shepherds[,] . . . the religion of the inhabitants, . . . their inclinations, riches, numbers, commerce, manners, and customs” to the causal inventory, concluding that laws “should be adapted in such a manner to the people for whom they are framed that it should be a great chance if those of one nation suit another.”54 Professor Iain Stewart’s analysis shows both thinkers combined a commitment to the division of governmental labor with attention to the distribution of political power, though Montesquieu recast Aristotle’s entirely political framework in legal terms.55 And, as Professor Keegan Callanan establishes, this was no casual resemblance: Montesquieu directly appropriated Aristotle’s concept of the regime as the organizing principle of political life and his method of analyzing how regime types shape citizens’ character.56
The contrast with the natural law school sharpens the point. Grotius, Pufendorf, and their successors worked deductively — inferring universal legal rules from abstract reason and a hypothesized social contract.57 Writing in this Review’s pages 110 years ago, Professor Eugen Ehrlich — widely regarded as the founder of “the discipline of the sociology of law”58 — identified Montesquieu as fundamentally opposed to that tradition. Where natural law theorists postulated uniform principles valid everywhere and always, Montesquieu insisted that law varies with its conditions.59 Ehrlich traced this orientation to Montesquieu’s early natural-history training, which instilled the habit of working with principles “not contrived a priori” but “derived from facts he collected, scrutinized, and turned over in his mind.”60 Over a decade, Montesquieu gained practical experience serving as an appellate judge (formally, président à mortier, because of the attendant headwear) in the Parlement of Bordeaux,61 although Robert Shackleton records that he “was not a great magistrate” and “was indeed unhappy in court;”62 his real education instead took place at the Academy of Bordeaux, whose culture of “[e]xperimentalism and hatred of the a priori”63 drove Montesquieu to “rigorous and ruthless” work — vivisecting frogs under a microscope, drowning ducks and geese64 — that would ultimately shape his approach to The Spirit of Laws.65 Professor Émile Durkheim made the same case in his 1892 Latin thesis, claiming Montesquieu as a founder of social science: the first thinker to study legal institutions as empirical phenomena shaped by discoverable social forces rather than as deductions from first principles.66
The constitutional implications are considerable. An Aristotelian political scientist does his work by cataloguing existing arrangements and identifying the conditions under which they promote or undermine liberty.67 Montesquieu went further. In fact, Montesquieu’s empiricism ran so deep that he declined to be bound by his own typologies. Despite organizing The Spirit of Laws around republics, monarchies, and despotisms, he described England — conventionally classed as a monarchy — as a nation where the republic concealed itself beneath monarchical forms.68 The remark is a small but telling piece of evidence: The thinker that formalists claim as an intellectual ancestor treated his own categories as descriptive conveniences to be overridden when functional reality warranted, not as binding classifications dictating legal consequences. Accordingly, when formalists draw categorical imperatives from Book XI, Chapter 6, they are reading Aristotle as though he were Plato — converting empirical observation into ideal form.69
D. Observation, Not Prescription
The Aristotelian character of Montesquieu’s enterprise is further confirmed by the inductive structure of The Spirit of Laws itself. The work catalogs an extraordinary range of factors shaping legal systems: climate, geography, commerce, religion, population, and customs.70 Montesquieu illustrated the dangers of ignoring these factors through examples of failed legal transplantation: Cretan theft laws that worked harmoniously when brought to Sparta proved incoherent when carried further to Rome, where they bore no relationship to Rome’s existing civil-law framework.71 And Montesquieu was candid about his enterprise’s limits, acknowledging uncertainty about whether England actually enjoyed the liberty its laws were designed to produce and declaring it sufficient to examine the legal framework without enquiring further.72 As Ehrlich expressed it, Montesquieu concerned himself with “what really is,” not “what should be.”73 The lesson Montesquieu drew from studying Crete’s laws in Sparta and Rome was simple: Legal arrangements cannot be abstracted from the conditions sustaining them.74 Extracting universal rules from Montesquieu’s catalogue of sociopolitical arrangements, then, does not merely misread the conclusion; it misconceives the enterprise.
E. Liberty as Effect, Not Form
Montesquieu’s Aristotelian methodology culminates in a functional rather than formal definition of political liberty — and inasmuch as he prescribed at all, Montesquieu did so to advance this conception.75 Liberty, according to the oracle, is not a particular institutional arrangement but a felt condition: the “tranquillity of mind arising from the opinion each person has of his safety,” achieved when government is constituted such that no individual fears another.76 Professor Laurence Claus confirms this reading. Montesquieu’s appeals to essentialism — his insistence on dividing governmental powers along categorical lines — obscured the functional “criterion” that actually animated his framework: “not whether powers differ in kind, but whether apportionment will prevent actors from conclusively determining the reach of their own powers.”77 That is a test of effects, not forms.78 Thus, in the final analysis, Montesquieu’s vast enquiry into the conditions that promote liberty distills to a simple prescription: “[P]ower should be a check to power.”79
Montesquieu applied this functional logic of liberty to the specific question of how executive officers should be organized. In a passage Vermeule recently unearthed from Montesquieu’s Pensées (a collection of largely unpublished writings unnoticed in legal literature), Montesquieu posited an inverse relationship between magisterial autonomy and citizens’ liberty: Where magistrates are “free” in the sense of autonomous from superior authority, the people they regulate are correspondingly less free; where magistrates are “enslaved” by subordination to an overarching Executive, the conditions for public liberty are most favorable.80 The observation is characteristically empirical — drawn from “an analysis of the” English and Dutch “pathologies,”81 not deduced from first principles — and it evaluates institutional arrangements by their consequences for the governed. Whatever one concludes about Montesquieu’s specific prescription, the passage further establishes that he approached executive design through the same consequentialist lens this Note has identified in his treatment of the balance of powers.
II.
Even functionalists who correctly identify Montesquieu’s methodology face a problem their jurisprudence has not adequately addressed: His framework was built for a constitutional order that no longer exists.82 Three of its features — the class-based structure inherited from Polybius, the conception of judicial power as invisible and negligible, and the complete absence of public law adjudication — fit poorly with modern American constitutionalism.
A. The Polybian Inheritance
Montesquieu’s balance of powers wasn’t conjured from first principles. It transformed a received tradition. Polybius, writing on the rise of Rome in the second century B.C., theorized that simple constitutional forms are inherently unstable — monarchy degenerating into tyranny, aristocracy into oligarchy, democracy into mob rule — in a recurring cycle he called anacyclosis.83 Rome escaped this fate, Polybius argued, by combining all three elements into a single system, so that each would restrain the excesses of the others.84 The key mechanism was not the separation of governmental functions but the balancing of social forces: The Consuls (who possessed “almost uncontrolled” power when prosecuting wars) represented monarchical authority;85 the unelected Senate (which, among other powers, exclusively controlled “the treasury, all revenue and expenditure”) depended on aristocratic deliberation;86 and the popular Assemblies (which served as “the only court which may try on capital charges” and “most important of all . . . deliberate[d] on the question of war and peace”)87 stood for democratic participation.88
The Founders knew this tradition well. Adams devoted sustained attention to Polybius in his Defence of the Constitutions.89 Indeed, classical references at the Constitutional Convention were so pervasive that “Franklin rose in despair” when “[t]he Convention threatened to degenerate into a classical meeting.”90 Montesquieu, calling Polybius “[t]hat judicious writer,”91 retained his class dimension throughout Book XI92: “[P]ersons distinguished by their birth, riches, or honours,” Montesquieu maintained, should not “be confounded with the common people”93 — a proposition both he and the Founders thought would be well served by bicameralism.94 And as Professor Maurice J.C. Vile has noted, Montesquieu’s references to the “three powers” sometimes meant the King, Lords, and Commons — i.e., the Polybian social estates of the one, the few, and the many — instead of the functional triad of powers distributed among the legislature, executive, and judiciary.95
B. The Invisible Judiciary
Montesquieu described the judiciary in terms bearing no discernible relationship to modern American practice. Of the three governmental powers, he wrote, “the judiciary is in some measure next to nothing,” leaving only two (executive and legislative) that truly counted in his mind.96 He envisioned not professional judges but temporary tribunals composed of laypeople, assembled for particular cases and dissolved once their work was complete.97 Judges were to function as nothing more than the inert media through which legislative language passed — ”mere passive beings, incapable of moderating either [the law’s] force or rigour.”98
Claus identified the underlying error: Montesquieu equated the entire judicial function with the factfinding work of juries — similar to Guernsey’s modern-day Jurats99 — failing to grasp that English courts elaborated legal rules through their decisions.100 He understood neither the common law nor precedent’s binding force within a judicial hierarchy.101 Claus poses the uncomfortable counterfactual: Had Montesquieu appreciated that English judges both found facts and made law, his framework would have required classifying judicial lawmaking as an exercise of legislative power — a conclusion that in turn collapses the tripartite scheme from within.102
The American judiciary that emerged could hardly be more distant from this vision. From Marbury’s establishment of judicial review to Chevron’s recent overruling, federal courts have exercised powers Montesquieu never contemplated.103 Hamilton began this transmutation in Federalist No. 78, appropriating Montesquieu’s vocabulary of judicial weakness while simultaneously embracing a judiciary vested with the power to pronounce legislative acts unconstitutional.104 Vile documents the intellectual pathway through Blackstone, who served as “the essential” intermediary between Montesquieu’s conception of judging and Chief Justice Marshall’s practice of the same.105 But the distance between Montesquieu’s “next to nothing” and the modern judiciary’s constitutional supremacy is not a gap formalist doctrine can bridge by citation alone.
C. The Missing Jurisdiction
A third structural gap has received less attention but is equally consequential. Montesquieu’s definition of judicial power is strikingly narrow: The magistrate “determines the disputes that arise between individuals.”106 Absent entirely is any role for the judiciary in disputes between the citizen and the state — what modern lawyers call public law. Montesquieu’s judiciary cannot review executive action, cannot invalidate legislation, and cannot police turf disputes between the political branches. By omitting all internal executive acts from judicial cognizance, Montesquieu leaves the boundary between executive authority and judicial power gravely indeterminate.107
But the gap between Montesquieu’s judiciary and America’s runs deeper than jurisdiction. Professor Michael Zuckert catalogued four fundamental points of divergence: Montesquieu’s judiciary “is essentially the jury”; it operates “via strict subordination” to legislative text rather than “pass[ing] judgment on the laws” themselves; it “is eminently a popular branch,” unlike today’s branch staffed by elite lawyers; and it “plays no part in the scheme of checks and balances,” whereas the American judiciary became “the granddaddy of all checking institutions.”108 The Convention inverted every one of these features, “turn[ing] the jobs” of three separate institutions “over to the judiciary” and arming it with the very powers Montesquieu denied it109 — producing what Professors Nikolas Bowie and Daphna Renan call a “juristocratic separation of powers.”110 Hugo Toudic and Céline Spector confirm: Montesquieu “had no notion of the judiciary serving as a constitutional court.”111 Instead, “[t]he honor of that innovation is generally held to belong to the Americans.”112
III.
The structural gaps identified in Part II don’t render Montesquieu irrelevant. Much can be gained by reprising his method of enquiry and his animating commitment to dispersing authority as liberty’s best safeguard. Invoking his authority, however, requires acknowledging the distance between his framework and modern practice.
A. Independent Agencies and the Logic of Nondelegation
Consider independent agencies — the perennial target of the Court’s formalist revival.113 For Montesquieu, distributing powers served a functional purpose: preventing tyranny through the checking of power by power.114 But for the Court’s new formalism, as Professor Noah Rosenblum argues, separation has become “a sacred practice” valued for its own sake.115 Yet even the First Congress didn’t follow formalist orthodoxy: Professor Christine Chabot documents seventy-one sets of statutory provisions (from that Congress) inconsistent with conventional, originalist accounts of unitary executive power.116
Independent agencies, vested with regulatory authority and partially insulated from presidential control, can plausibly be understood as more faithful to Montesquieuian principles than the formalist alternative. By distributing regulatory authority across institutional actors with different constituencies and incentive structures, such agencies replicate “the checking” the Polybian-Montesquieuian tradition was designed to achieve.117 The formalist demand for a unitary executive branch answerable only to the President thus “paradoxically”118 consolidates power in the manner Montesquieu found most dangerous.119 As Vermeule rightly observes, separation of powers and the unitary executive thesis concern analytically distinct questions: the former addresses horizontal distribution among the branches, the latter vertical hierarchy within the executive.120 Montesquieu’s warnings about concentrated power in Book XI speak to the horizontal question. They don’t resolve the vertical one. A court invoking separation of powers to mandate presidential control over subordinate officers thus deploys a principle designed for one problem to answer another.
Similar reasoning applies to the nondelegation doctrine. A judicially enforced prohibition on legislative delegation — one that finds no textual basis in the Constitution and relies on maxims Montesquieu never intended as rules121 — would amount to “siding with the Anti-Federalists” against the institutional choices the Framers actually made.122 On Montesquieu’s own terms, the question isn’t whether a delegation transgresses a categorical boundary but whether the particular delegation at issue leaves authority effectively checked. And as the next section demonstrates, that enquiry requires empirics.
B. The Empirical Question
Montesquieu didn’t pronounce a particular configuration correct in the abstract; he examined whether arrangements actually produced liberty.123 The implication for modern courts is that institutional design presents an empirical question, not a taxonomic one. The enquiry asks whether a given arrangement forestalls the dangerous concentration of authority — measured by its effects on the governed, not by reference to labels.
This empirical orientation demands engagement with institutional reality over theoretical doctrinal purity. Does an independent agency, insulated from direct presidential control, diffuse authority in ways that promote liberty? Does the combination of rulemaking and adjudicative functions within a single body generate the kind of concentrated power Montesquieu warned against, or does it operate under sufficient constraints — judicial review, congressional oversight, budgetary cotrol — to prevent abuse? These are questions of empirical fact and institutional design, not ones resolvable by merely looking to the form a particular power takes.124
Consider, for instance, the arrangement invalidated in Jarkesy: the SEC’s exercise of adjudicative authority over civil penalties.125 The formalist majority, relying in part on Montesquieu, treated the combining of prosecutorial and adjudicative functions as a per se separation-of-powers violation.126 A Montesquieuian analysis would ask a different question — whether the arrangement, in practice, concentrated unchecked authority in ways that threatened the liberty of the governed. The answer is not obvious. SEC administrative proceedings are subject to appellate judicial review, governed by the Administrative Procedure Act’s procedural protections, constrained by congressional oversight of the agency’s budget and jurisdiction, and limited by due process requirements the agency cannot waive.127 Whether these constraints suffice is debatable, but it is an empirical debate about institutional design — precisely the kind of enquiry Montesquieu’s method demands and precisely the kind formalism forecloses.128
Madison’s own treatment of Montesquieu illustrates the approach. Even Madison’s sharpest critique — his 1793 “Helvidius” essays, which accused both Locke and Montesquieu of being “evidently warped by a regard to the particular government of England” — was confined to the narrow question of whether treaty and war powers are executive or legislative.129 On the general separation principle, by contrast, Madison’s praise was unqualified: Montesquieu’s contribution lay in “enforcing the reasons and the importance of avoiding a confusion of the several powers of government,” rather “than by enumerating and defining the powers which belong to each particular class.”130 The distinction is telling. Madison read Montesquieu as a thinker who explained why power must be dispersed, not as one who specified how to achieve that aim, let alone in the contingent institutional circumstances of a nascent America. The modern Court has inverted that emphasis.
IV.
The conclusions above carry particular implications for originalist methodology, which claims to recover (and ground interpretation in) the intellectual context in which the Constitution was ratified.131 While the historical record is too rich for this Note to fully canvass, the portions surveyed here confirm that the Founding generation engaged seriously with Montesquieu, understood his empirical character, and, taking seriously his admonition not to mechanically transplant laws from Crete to Rome, adapted his prescriptions to American conditions.132 For starters, Montesquieu was the most frequently cited European thinker in American political writings between 1760 and 1805, appearing more often than Locke, Blackstone, or any other secular authority.133 He permeated the Federalist Papers, the Anti-Federalist writings, and the Convention debates.134 Both Federalists and Anti-Federalists claimed Montesquieu for their side135 — itself evidence of sustained, interpretive engagement with his life’s work.
Madison’s treatment in Federalist No. 47 remains the paradigm: He examined Montesquieu’s source, analyzed the English constitution, and concluded that the maxim prohibited only the concentration of “whole power[s].”136 Governmental practice “in the early republic” was, as Rosenblum establishes, “flexible and pragmatic, without a clear line separating powers from each other.”137 Indeed, Madison’s own survey of state constitutions found no instance in which strict separation was actually maintained.138 And Chabot’s documentation of seventy-one First Congress statutes inconsistent with unitary executive orthodoxy, together with Professors Julian Davis Mortenson and Nicholas Bagley’s analysis of the post roads debates as incompatible with a strong-form nondelegation doctrine, confirms the pattern.139 Recovering the historical Montesquieu, Rosenblum therefore argues, “point[s] away from the Court’s new separation of powers formalism on the Court’s own terms.”140
One might object that the Founders explicitly departed from Montesquieu on judicial power, creating a permanent judiciary with authority to review the constitutionality of legislation. This is true — and the departure was knowing. Hamilton borrowed Montesquieu’s language of judicial passivity,141 while authorizing a judicial role that was anything but. The resulting synthesis was distinctively American: neither pure Montesquieu nor pure rejection, but a creative transformation of his principles for a society the Founders understood to differ from his. Modern courts should approach his work with comparable sophistication.142
Conclusion
The Supreme Court has made Montesquieu a regular presence in separation-of-powers disputes, but it hasn’t reckoned with what he actually wrote. Formalists invoke him as a Platonic idealist when he was an Aristotelian empiricist. Functionalists haven’t addressed how far modern institutions have drifted from Montesquieu’s: The class-based legislature is gone, judicial power has been transformed beyond recognition, and public law adjudication has emerged from whole cloth.
None of this makes Montesquieu irrelevant. His central insight — liberty requires fragmenting and precariously balancing authority against itself — remains as vital as ever. And his Aristotelian method provides a model for more rigorous constitutional analysis than either formalist deduction or functionalist improvisation.
But citation carries responsibilities. Courts invoking Montesquieu should engage with his text, acknowledge the distance between his framework and modern institutions, and recognize his method counsels against the very formalism claiming his authority. Montesquieu’s concern was preventing the accumulation of arbitrary power, not enforcing a rigid tripartite architecture — and arrangements distributing authority across multiple centers of accountability may serve his purposes better than concentrating executive power in a single pair of hands.
Montesquieu’s own warning about uprooting laws from their native conditions applies with particular force to the transplantation of his own maxims: “[W]e must not separate the Laws from the Circumstances in which they were made.”143 The Montesquieu who emerges from careful reading is more useful than the mechanical oracle that modern jurisprudence has constructed — and recovering him would bring the Court closer to the tradition it rightly claims to honor.