Legal Theory Lexicon 117: Constitutional Theory

Introduction

Law students at different law schools encounter the course in constitutional law at different points in their legal education. At some law schools constitutional law is a second-semester first-year course, but conlaw is sometimes a first-semester 1L course and at a significant number of law schools, the course is an upper-division elective or requirement. Even if you do not take constitutional law in your first year, you are almost certain to encounter constitutional issues in other courses. Personal jurisdiction is a standard topic in civil procedure, and most of the personal jurisdiction cases involve interpretation of the Due Process Clauses of the Fifth and Fourteenth Amendments. Property courses frequently cover the Takings Clause of the Fifth Amendment, and the torts course might include the First Amendment limitations on the defamation torts via the Supreme Court’s decision in New York Times Co. v. Sullivan. So, constitutional doctrine is pervasive in the first year and throughout law school. Constitutional theory addresses a different set of questions, including: what justifies the constitution, which institutions should have the power to decide constitutional questions, and how should constitutional actors go about deciding what the Constitution means?

These questions sit just beneath the surface of the cases you read. When a court asks whether the Constitution should be interpreted according to its original meaning or its evolving meaning, that is a question of constitutional theory. When commentators argue about whether unelected judges should have the power to strike down laws passed by an elected legislature, that too is constitutional theory. So too is the question of why the Constitution binds us at all, given that it was ratified by an unrepresentative group of people who are now long dead. The cases assume answers to these questions; constitutional theory makes the questions explicit and examines the answers.

This entry provides a map. It begins with the idea of a constitution and the basic distinction between provisions that allocate government power and provisions that protect individual rights. It then offers a short history of American constitutional theory, introducing the major ideas as they emerged. Next it takes up the central interpretive debate between originalism and living constitutionalism. Finally, it offers a brief introduction to comparative constitutional theory, which reminds us that the American constitutional arrangement is one option among many rather than the only way a constitutional democracy might be designed.

Constitutional theory is covered extensively in various Legal Theory Lexicon entries. This entry aims to provide a synoptic overview that will give students taking the conlaw course a sense of the big picture and major themes in constitutional theory.

The Idea of a Constitution

What is a constitution? At the most basic level, a constitution is the framework that constitutes a government — it creates the institutions of the state, specifies how they are composed, and defines the powers they may exercise. The word itself carries this meaning: to constitute something is to bring it into being. The United States Constitution creates a Congress, a President, and a system of federal courts, and it specifies how each is selected and what each may do. A constitution in this sense is foundational. It is the law that stands behind ordinary law, the framework within which legislatures legislate and courts decide cases and controversies.

Constitutions typically do more than create institutions. They also limit what those institutions may do. This is the idea of constitutionalism — the principle that government power should be limited by law, and that even the highest officials are bound by rules they cannot change at will. A government with unlimited power is not a constitutional government, even if it has a document called a constitution.

Constitutions usually secure these limits through entrenchment, which means they are harder to change than ordinary legislation. An ordinary statute can be repealed by a later statute, but the United States Constitution can be amended only through the demanding process of Article V, which usually requires two-thirds supermajorities in Congress and ratification by three-quarters of the states. Entrenchment is what allows a constitution to bind the future, placing certain commitments beyond the reach of today’s legislative majority.

It is common to distinguish written from unwritten constitutions. The United States has a written constitution — a single canonical document, supplemented by its amendments. The United Kingdom is the standard example of an unwritten constitution: it has no single founding document, and its constitutional arrangements are found in statutes, judicial decisions, and longstanding conventions. The distinction is real but can be overstated. Even a written constitution like the American one is surrounded by a vast body of unwritten understandings, and even an unwritten constitution like the British one includes important written sources. What matters is less the existence of a single document than the existence of fundamental norms that structure and constrain government.

Finally, it is worth distinguishing the Constitution (the written document) from constitutional law. The Constitution is a text. Constitutional law is the body of doctrine that implements the text, mostly through judicial interpretation but also through constitutional practices of Congress and the executive branch. Most of what you study in a constitutional law course is not explicit in the text of the Constitution at all: the tiers of scrutiny, the categories of unprotected speech, and the tests for state action are doctrinal constructs that courts have developed over time.

The identification of the Constitution with constitutional law can be misleading for another reason: much of the constitution operates outside the courts. Many constitutional questions are never litigated and are settled instead by the political branches: whether to go to war, how the houses of Congress organize their proceedings, and what the Senate’s role of “advice and consent” requires are largely worked out by Congress and the President rather than by judges. Some constitutional norms are what scholars call underenforced — the courts decline to enforce them to their full conceptual limits, often because the judiciary regards the question as better suited to the political process, leaving the political branches to honor the norm in the first instance. Doctrines that require deference to Congress may result in constitutional norms that are underenforced or not enforced at all. And constitutional practice is shaped by longstanding conventions and traditions that courts do not enforce but that constitutional actors treat as binding. The constitution, in short, is not only what courts say it is; it is also a framework that legislators, executives, and citizens interpret and apply for themselves.

Powers and Rights

The provisions of the Constitution can be divided into two types (powers and rights), and learning to tell them apart is one of the most useful things a student can do early on. Some provisions allocate government power — they say who gets to do what. Others protect individual rights — they say what government may not do to persons or citizens. Recognizing which kind of provision is at stake clarifies what the case is really about.

Start with the power-allocating provisions. These come in two main varieties. The first concerns federalism — the division of authority between the national government and the states. Article I grants legislative powers to Congress, and it does so by enumeration: Congress may regulate interstate commerce, coin money, establish post offices, and exercise the other powers the Article lists. The premise of enumeration is that Congress has only the powers granted to it, not a general power to legislate on any subject. The Tenth Amendment states the other side of this arrangement, providing that the powers not delegated to the United States are reserved to the states or to the people. Federalism questions — whether a given subject is for Congress or for the states — are questions about this division of authority.

The second kind of power-allocating provision concerns the separation of powers — the division of authority among the branches of the national government. Here the key provisions are the vesting clauses that open the first three Articles. Article I vests the legislative power in Congress, Article II vests the executive power in the President, and Article III vests the judicial power in the federal courts. These clauses distribute the basic functions of government among three distinct branches, and separation-of-powers questions — whether some action belongs to the legislature, the executive, or the judiciary — are questions about this distribution.

Now turn to the individual rights provisions. These do not allocate power; they limit it. These provisions identify things the government may not do to persons, or interests it may not invade without sufficient justification. The First Amendment is a familiar example: it protects the freedoms of speech, press, religion, and assembly against governmental abridgment. The Fourteenth Amendment is another: its Due Process Clause protects life, liberty, and property against deprivation without due process of law, and its Equal Protection Clause forbids the states from denying any person the equal protection of the laws. The two amendments illustrate a feature of the Constitution’s rights provisions worth noticing at the outset: some originally limited only the federal government and others limit the states. The First Amendment by its terms restrains Congress, while the Fourteenth Amendment expressly restrains the states — though much of the Bill of Rights, including the First Amendment, has come to apply against the states as well through the doctrine of incorporation, which we take up below. When a court asks whether a law violates someone’s constitutional rights, it is working with provisions of this second kind.

Although almost all of the United States Constitution regulates government, there are exceptions. The most important of these is the Thirteenth Amendment, which provides: “Neither slavery nor involuntary servitude, except as a punishment for crime whereof the party shall have been duly convicted, shall exist within the United States, or any place subject to their jurisdiction.” This provision applies to private individuals: if an ordinary citizen enslaves another person, their action is unconstitutional.

A Short History of American Constitutional Theory

Constitutional theory in America has a history, and the major ideas are easier to understand when you see the problems they were responses to. What follows is a very brief and simplified chronological sketch, introducing the central theoretical concepts as they emerged.

The Founding and Ratification. American constitutional theory begins with the debate over whether to ratify the Constitution. The Federalists, whose most famous arguments appear in The Federalist, defended the proposed Constitution; the Anti-Federalists opposed it or sought amendments to protect liberty and the states. The most celebrated contribution from this period is Madison’s Federalist No. 10, which addresses the problem of faction. By “faction,” Madison meant a group of citizens united by some common interest or passion adverse to the rights of others or to the interests of the community as a whole — an idea closely related to the modern phrase “special interest group.” Madison argued that the cure for the dangers of faction lay in the very size and diversity of the extended republic the Constitution would create: in a large republic, the multiplicity of interests would make it harder for any single faction to form a tyrannical majority. In addition, the Constitution creates horizontal separation of powers and checks and balances at the national level, dividing power between the Congress, the President, and the judiciary. The Constitution also divides power between the federal government and the states. Federalist No. 10 introduced enduring themes of American constitutional theory — the danger of majority faction, the design of institutions to channel and check self-interest, and the defense of the extended commercial republic — and it remains among the most studied texts in all of American political thought.

Marbury v. Madison and Judicial Review. In 1803, Marbury v. Madison is conventionally said to have established that the federal courts have the power to declare statutes unconstitutional. That familiar framing, however, deserves two qualifications. First, the very phrase “judicial review” and the idea of it as a distinct judicial “power” were not introduced until the late nineteenth century; the Marshall Court did not understand itself to be claiming a special power by that name. As Philip Hamburger has argued, what Marbury reflects is better understood as the ordinary judicial duty to decide cases according to law: when a statute conflicts with the Constitution, which is the higher law, the court’s duty is simply to follow the higher law in deciding the case before it. On this view, the court does not exercise a power to strike down legislation so much as discharge its duty to apply the governing law. Second, what we now call the “power of judicial review” was already well established before Marbury. Marbury raised a question that has never gone away: who has the final word on what the Constitution means? One historically important answer is departmentalism — the view that each branch of government interprets the Constitution for itself, so that the courts’ interpretations bind the parties before them but do not necessarily settle constitutional meaning for the other branches. The tension between judicial supremacy and departmentalism runs throughout American constitutional theory.

The Antebellum Period and Dred Scott. Before the Civil War, constitutional theory was preoccupied with slavery and the nature of the union. Dred Scott v. Sandford (1857), in which the Court opined that African Americans could not be citizens and stated in dictum that Congress could not prohibit slavery in the territories, is the great cautionary tale of this period. It illustrates the limits of judicial review as a mechanism for settling the deepest moral and political conflicts: rather than resolving the crisis over slavery, the decision inflamed it and helped precipitate the civil war.

Reconstruction and the Fourteenth Amendment. The Civil War and its aftermath produced what scholars often call the “second founding”: the Thirteenth, Fourteenth, and Fifteenth Amendments, which abolished slavery, guaranteed due process and equal protection against the states, and protected voting rights. The Fourteenth Amendment in particular transformed the constitutional order. It shifted the federal-state balance by subjecting the states to important new federal constraints, and over time it became the vehicle for incorporation — the doctrine through which most of the protections in the Bill of Rights, which had originally limited only the federal government, came to apply against the states as well. Much of contemporary constitutional law derives from Section One of the Fourteenth Amendment, including the Citizenship Clause, the Due Process Clause, and the Equal Protection Clause — as well as the Privileges or Immunities Clause, which was virtually erased by the Supreme Court in the Slaughterhouse Cases.

The Lochner Era and Its Critics. From the 1890s into the 1930s, the Supreme Court used the Due Process Clause to protect economic liberties, most famously in Lochner v. New York (1905), which struck down a maximum-hours law for bakers. Lochner involved what is now called “substantive due process” as the source of implied fundamental rights. Critics charged that the Court was reading its own laissez-faire economic philosophy into the Constitution. The most important theoretical response came earlier from James Bradley Thayer, whose work argued for judicial deference to legislatures: on Thayer’s view, a court should invalidate a statute only when its unconstitutionality is so clear that it is not open to rational question — the “clear mistake” rule. Justice Holmes gave the critique its most memorable expression in his Lochner dissent, objecting that the Constitution does not enact any particular economic theory and that judges should not impose their own. Thayerian deference remains a live position in debates about the proper role of the courts.

The New Deal Settlement and Footnote Four. The conflict between the Court and the elected branches came to a head in the 1930s, when the Court struck down New Deal legislation and President Roosevelt responded with his court-packing plan. After 1937 — the famous “switch in time” — the Court abandoned economic substantive due process and adopted a deferential posture toward economic regulation. But deference raised a question: if courts defer to legislatures, when, if ever, is aggressive judicial review appropriate? The most influential answer appeared in footnote four of United States v. Carolene Products (1938), which suggested that heightened scrutiny might be warranted in three circumstances: when legislation appears to violate a specific constitutional prohibition, when it restricts the political processes that ordinarily protect minorities, and when it reflects prejudice against “discrete and insular minorities.” Footnote four is the seed of representation-reinforcement theory, which we encounter again below in connection with the work of John Hart Ely.

The Warren Court and the Countermajoritarian Difficulty. Under Chief Justice Earl Warren (1953–1969), the Court issued a series of landmark decisions expanding individual rights and equality, beginning with Brown v. Board of Education (1954). The Warren Court’s activism prompted intense theoretical debate about the legitimacy of judicial review in a democracy. Alexander Bickel gave the problem its enduring name: the countermajoritarian difficulty — the worry that when unelected, life-tenured judges strike down laws enacted by elected legislatures, they act against the will of the majority and thus in tension with democratic self-government. The countermajoritarian difficulty became the defining problem of late-twentieth-century constitutional theory, and much subsequent work can be understood as an attempt to answer it. One influential answer was John Hart Ely’s representation-reinforcement theory, articulated in his famous book, Democracy and Distrust. Building on footnote four in Carolene Products, Ely argued that judicial review is democratically legitimate when it polices the channels of political participation and protects minorities from prejudice, rather than imposing the judges’ own values. We return to Ely’s view in the next section.

The Rise of Originalism. Although originalist ideas go back to the founding era, originalism emerged as a distinct theory of constitutional interpretation in the 1970s and 1980s, in significant part as a conservative reaction to the perceived excesses of the Warren and Burger Courts. The early versions emphasized the original intentions of the Framers, and they were offered as a way of constraining judges and answering the countermajoritarian difficulty: if judges are bound by the original meaning of the text, they cannot simply impose their own values. Critics raised powerful objections to original-intent originalism, and originalists responded by shifting their focus from the intentions of the Framers to the original public meaning of the constitutional text — the meaning the words would have had to ordinary readers at the time of enactment. Over the following decades, originalism developed into a sophisticated body of theory, and both originalism and its principal rival, living constitutionalism, became central to contemporary constitutional debate. Those two positions are the subject of the next section.

Originalism and Living Constitutionalism

The central interpretive debate in contemporary American constitutional theory is the debate between originalism and living constitutionalism. The question dividing them is fundamental: when we ask what the Constitution means, are we bound by the meaning the text had when it was adopted, or can that meaning legitimately change over time? Almost every interpretive dispute you will encounter — about the Second Amendment, the Fourteenth Amendment, the scope of executive power — sits somewhere on the terrain mapped by this debate.

Originalism. Originalists hold that the meaning of the constitutional text is fixed at the time each provision is adopted, and that this original meaning is binding on interpreters today. Two ideas are central. The first is the fixation thesis: the meaning of the text was fixed when it was framed and ratified, just as the meaning of any historical document is fixed by the linguistic and contextual facts of its time. The second is the constraint principle: constitutional actors, and judges in particular, ought to be bound by that original meaning. Together, fixation and constraint capture the core originalist commitment — that the Constitution means what it meant, and that its meaning should govern.

Originalism has changed over time. The early originalism of the 1970s and 1980s emphasized original intent — the subjective intentions of the Framers who drafted the document. Critics objected that this approach faced serious difficulties: many framers with many intentions, intentions pitched at different levels of generality, and the puzzle of why the unenacted intentions of particular individuals should bind anyone. In response, most originalists shifted to original public meaning — the meaning the words of the text would have had to an ordinary, reasonable reader at the time of enactment. The object of interpretation on this view is not anyone’s private intentions but the public meaning of the words actually adopted. The most prominent version of originalism is called “Public Meaning Originalism.”

Modern originalist theory also distinguishes interpretation from construction. Interpretation is the activity of discovering the linguistic meaning or communicative content of the text. Construction is the activity of determining the text’s legal effect — of translating its meaning into rules of constitutional law and applying it to particular cases. The distinction matters because the constitutional text is sometimes vague or open-textured, and where it is, interpretation alone may not decide a case; construction is required to fill the gap. This entry treats the interpretation-construction distinction only in passing; it is treated more fully in Legal Theory Lexicon: Interpretation and Construction.

Living Constitutionalism. Living constitutionalists hold, in contrast, that the meaning of the Constitution can legitimately evolve over time, so that the document can be adapted to changing circumstances and values without formal amendment. The animating idea is that a constitution written in the eighteenth century, and difficult to amend, must be capable of growth if it is to govern a society utterly transformed in its technology, economy, and moral understanding. Living constitutionalism is not a single theory but a diverse family of approaches.

The most prominent form of living constitutionalism is constitutional pluralism, which holds that constitutional interpretation and construction properly draw on multiple modalities of argument rather than any single master criterion. On this view, the resources of constitutional practice include the text, historical practice, judicial precedent, constitutional values, and institutional capacities — and constitutional reasoning consists in marshaling and weighing these modalities, none of which is automatically supreme. Constitutional pluralism is treated more fully in Legal Theory Lexicon 100: Constitutional Pluralism.

There are many other forms of living constitutionalism as well, including common-law constitutionalism, associated with David Strauss, which understands constitutional law as developing incrementally through judicial decisions in the manner of the common law, and the moral reading, associated with Ronald Dworkin, which interprets the Constitution’s abstract moral language as stating principles whose content must be worked out through moral judgment.

Constitutional pluralism, common-law constitutionalism, and the moral readings approach are forms of judicial supremacy, but contemporary constitutional theory includes views that allocate the primary authority over constitutional matters to Congress. One such theory is representation-reinforcement, associated with John Hart Ely and introduced in the previous section: judges should not impose their own moral views, but should intervene to keep the channels of political change open and to protect minorities whom the political process has failed. An even more deferential position is found in the revival of Thayerianism among some contemporary progressive scholars, including Samuel Moyn, Ryan Doerfler, Nicholas Bowie, and Daphna Renan, who urge a substantial reduction in the scope of judicial review and a corresponding return of constitutional decisionmaking to the elected branches. These approaches differ significantly, but they share the conviction — or at least the implication — that constitutional actors should not consider themselves bound by the constitutional text.

A Short Introduction to Comparative Constitutional Theory

American constitutional theory is, on the whole, parochial. It tends to theorize from the American case alone — as if the structures, doctrines, and questions familiar from the United States Constitution were the natural or even the only form that constitutionalism can take. Comparative constitutional theory corrects this tendency by attending to how other constitutional democracies have answered the same basic questions, often in strikingly different ways. A few examples convey the value of the comparative perspective.

Consider first the constitutions that protect positive rights. The United States Constitution is predominantly a charter of negative rights — it tells the government what it may not do, but it generally does not oblige the government to provide anything. Other constitutions are different. The Constitution of South Africa is the leading example: it guarantees affirmative entitlements such as access to housing, health care, food, water, and education, and the South African Constitutional Court has developed doctrines for enforcing these guarantees against the government. Positive-rights constitutions raise questions that the American negative-rights tradition tends to keep out of view — about the justiciability of social and economic rights, the role of courts in matters of resource allocation, and the meaning of constitutional equality in conditions of material deprivation.

Consider next the alternatives to American-style judicial review. In the United States, judicial review is typically understood in its “strong” form: when a court holds a statute unconstitutional, that judgment ordinarily settles the matter, and the legislature cannot override it except by the difficult route of constitutional amendment. Other systems have devised arrangements that allocate the last word differently. The notwithstanding clause of the Canadian Charter of Rights and Freedoms — section 33 — permits a legislature to declare that a statute shall operate notwithstanding certain Charter rights, for a renewable period, thereby preserving a legislative check on judicial interpretation. Mechanisms of this kind, sometimes called “weak-form” judicial review, show that judicial review need not take the strong American form, and they reframe the countermajoritarian difficulty as a problem with more than one possible institutional solution.

Consider finally that comparative constitutional theory is not merely a catalog of foreign arrangements but a site of sophisticated theory in its own right. The work of Aileen Kavanagh is a useful example. Drawing primarily on non-American materials, Kavanagh has developed an account of collaborative constitutionalism, which reconceives the protection of constitutional rights as a shared enterprise among courts, legislatures, and executives rather than a contest in which one institution holds final authority over the others. Whether or not one finds the account persuasive, it illustrates that rich constitutional theory can be built on foundations other than the American case — and that doing so can illuminate possibilities the American debate, fixated on the finality of judicial review, tends to neglect. Kavanagh’s work is cited in the bibliography below.

Comparative constitutional law is its own vibrant field of study, and many American law schools have an elective course — but it is very rare for comparative constitutionalism to be introduced in the basic constitutional law course. Constitutional theory from outside the United States is almost entirely ignored in American law school classrooms.

Conclusion

Constitutional theory supplies the questions that lie behind the constitutional cases you read. What is a constitution, and why does it bind us? Which provisions allocate power, and which protect rights? How should the text be interpreted, and who should have the final say? And how do the answers given by American constitutional practice compare with the answers given elsewhere? You need not resolve these questions to study constitutional law, but recognizing them will deepen your understanding of the cases and of the arguments that lawyers and judges make within them. As your study advances, the other entries in this Lexicon that treat particular theories and concepts in greater depth — on originalism, interpretation and construction, the fixation thesis, judicial review, and related topics — will help you go further.

Bibliography

Alexander M. Bickel, The Least Dangerous Branch: The Supreme Court at the Bar of Politics (2d ed. 1986).

Ryan D. Doerfler & Samuel Moyn, Democratizing the Supreme Court, 109 Cal. L. Rev. 1703 (2021).

Ronald Dworkin, Freedom’s Law: The Moral Reading of the American Constitution (1996).

John Hart Ely, Democracy and Distrust: A Theory of Judicial Review (1980).

The Federalist No. 10 (James Madison) (Clinton Rossiter ed., 1961).

Philip Hamburger, Law and Judicial Duty (2008).

Aileen Kavanagh, The Collaborative Constitution (2023).

Lawrence B. Solum, The Fixation Thesis: The Role of Historical Fact in Original Meaning, 91 Notre Dame L. Rev. 1 (2015).

Lawrence B. Solum, Original Public Meaning, 2023 Mich. St. L. Rev. 807.

David A. Strauss, The Living Constitution (2010).

James B. Thayer, The Origin and Scope of the American Doctrine of Constitutional Law, 7 Harv. L. Rev. 129 (1893).

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