Fundamentals

What Constitutionalism Is and Why a Constitution Is Not Enough

By Daniel Sardá · Published on September 14, 2026

7 min read1,330 words

A constitution can organize power; constitutionalism requires that power face real limits that people can invoke.

Not every society with a constitution lives under a constitutional order in the stronger sense. A text can create offices, assign functions, and list rights; it is another matter whether those who exercise power are genuinely bound by those rules and can be held to account when they violate them.

That distinction lies at the heart of constitutionalism. More than a document, it is a doctrine and a practice: public authority must be limited by law, and those limits must matter even when they inconvenience the government of the day or a temporary majority.

Key idea: A constitution organizes power; constitutionalism seeks to prevent power from using that organization to place itself above the rules.

Constitutionalism: power under binding rules

In its ordinary sense, constitutionalism holds that political power is not legitimate merely because it exists, follows a custom, or was elected. It must also act within defined powers, respect procedures, and recognize spheres of freedom it cannot alter at will.

That is why a written constitution alone is not enough. It may be a valuable framework, but its effectiveness depends on its limits being public, binding, and enforceable. If an authority can reinterpret or disregard them without consequence, the text retains symbolic value while losing much of its role as a restraint on power.

This does not require a single institutional design. Countries differ in how they distribute authority, protect rights, or review laws. The common point is simpler: no one exercising public power should be the sole judge of the limits that bind them.

The term also has a specific historical use in Mexico, where it can refer to the movement led by Venustiano Carranza during the Mexican Revolution. That is not the subject of this article, which addresses the general political and legal concept.

A constitution, constitutional law, and a constitutional order are not the same

It helps to separate related concepts that are often blurred together.

A constitution is the body of fundamental rules—often collected in a text—that organizes institutions, powers, and procedures. It may establish how a government is elected, how laws are passed, or which rights are recognized.

Constitutionalism is the idea that this framework must place meaningful limits on power. It asks not only how the state is organized, but also what it is forbidden to do and how that prohibition is enforced.

Constitutional law, by contrast, is a legal field: it studies, interprets, and applies constitutional rules. It can describe an existing order without claiming that the order limits power adequately. A constitutional order is the effective structure of institutions and rules operating under a constitution; it does not automatically deserve to be called constitutionalist either.

The distinction matters because it prevents “constitutional” from becoming a term of praise. A rule may be formally included in a constitution and still expand an authority’s discretion or leave people without effective protection.

What makes a limit more than a promise

Constitutional limits can concern rights, procedures, or powers. Their function is to reduce arbitrariness: public decisions should depend on known rules, not merely on the preferences of those in command.

In practice, that objective usually rests on several institutional elements:

• Constitutional supremacy: lower-level rules and acts must be compatible with the applicable constitutional framework.
• Rights and guarantees: certain interests and freedoms receive protection against public decisions, along with ways to claim that protection.
• Distribution of functions: assigning different powers to different bodies makes it harder for a single institution to concentrate every decision.
• Checks and remedies: review, accountability, and challenge procedures make it possible to question acts that exceed an authority’s power or violate a guarantee.

The separation of powers illustrates this logic, though it does not exhaust constitutionalism. Dividing legislative, executive, and judicial functions seeks to make it harder for authority to accumulate in one center. Yet a nominal separation is not enough: it requires defined powers, incentives to exercise them, and conditions that keep checks from becoming merely decorative. Constitutional review addresses these mechanisms in greater detail.

Key idea: A constitutional limit does not merely prohibit something; it needs institutions and procedures that make the prohibition matter in particular cases.

Constitutional rigidity can contribute to that function by making it harder for ordinary authorities to change the rules that restrain them. It is not an automatic guarantee, however. A difficult amendment process can protect rights against passing impulses, but it can also preserve defective rules; its value depends on the institutional whole and on the avenues for correction it provides.

Legality, democracy, and supremacy: related, but not interchangeable

Acting under a law in force does not, by itself, resolve the constitutional question. Legality requires an authority to follow the applicable rules; constitutional supremacy adds another question: is that lower-level rule, or the act taken under it, compatible with the higher rule?

For example, a statute may have been enacted through the ordinary legislative procedure and still pose a constitutional problem if it invades a reserved power, disregards a guarantee, or contradicts a procedural requirement. Constitutionalism does not allow that objection to be dismissed merely by saying, “the law was voted on.”

Something similar applies to democracy. Democracy primarily answers who decides and through which procedures of participation or representation. Constitutionalism adds limits to what may simply be decided. It does not deny the value of majority decision; it rejects the idea that a momentary majority makes any decision legitimate merely by counting votes.

From a classical liberal perspective, that caution protects room for the lives, plans, and decisions of people who neither control government nor belong to the majority. General rules, individual rights, and divided powers can restrain arbitrariness. But it would be an overstatement to conclude that every regime calling itself constitutional guarantees freedom: rules must be interpreted, applied, and defended by institutions and citizens.

Key idea: Democracy may produce a decision; constitutionalism asks whether that decision respected the limits that make government compatible with established rights and powers.

Who checks the checkers?

The problem does not disappear when a court or review mechanism is created. Constitutional review can restrain abuses, but it also raises a legitimate debate about the weight of unelected judges relative to representative bodies. No formula is free of tension: independence, access for affected people, the quality of decisions, and compliance with judgments all matter.

It is therefore worth avoiding two simplifications. The first says every court protects rights; that is not always so. The second holds that any judicial review amounts to rule by judges; that is not so either. The constitutional question is precisely how to design checks that neither leave power unrestrained nor turn a checker into an unlimited authority.

Effectiveness also depends on institutional habits. When officials comply with adverse decisions, people can bring claims, and public bodies watch one another, a constitution has a better chance of operating as law. When checks are captured or remedies are inaccessible, constitutional language can survive without genuinely limiting power.

A substantive standard for evaluating power

Constitutionalism is not a label for celebrating every fundamental text, nor is it a promise of good political outcomes. It is a standard for examining power: what it may do, under which rules, subject to which checks, and what recourse a person has when those limits are ignored.

That perspective leads to more useful questions than the mere existence of a constitution: Are powers clear? Can rights be claimed? Are public decisions subject to review? Can checks act against power? A constitutional government worthy of the name begins there.

To explore a particular tradition that connects these limits with individual liberty and limited government, continue with liberal constitutionalism. For the role of guarantees and their enforceability, guarantist constitutionalism is a useful next step.

Sources consulted

• Stanford Encyclopedia of Philosophy, “Constitutionalism”.
• Diccionario del español de México, “constitucionalismo”.
• National Constitution Center, “Separation of Powers and Federalism”.