Fundamentals

Constitutional Rule of Law: What It Is and How It Limits Power

By Daniel Sardá · Published on September 18, 2026

6 min read1,282 words

A constitution limits power only when its rights, rules, and mechanisms of review can operate against public authorities.

A constitution can be a country's most solemn document and still fail to limit those who exercise power. The decisive question is not only whether a constitutional text exists, but whether public authorities are bound by it and whether individuals have ways to demand that limit.

The constitutional rule of law names precisely this institutional ideal: public power is subject to a higher constitution, recognizable rights, and procedures for reviewing its actions. It is neither a formula identical across all legal systems nor an automatic guarantee of liberty. It is a way of understanding that governing does not mean having the authority to decide everything.

Key idea: A constitution does not limit power merely because it is written down; it does so when its rules can prevail over a concrete decision by an authority.

More than obeying laws

It may seem enough for an administration to act under the authority of a statute. But a law can be duly enacted and still authorize arbitrary treatment, discriminate, or close off every avenue for challenging its effects. Formal legality therefore does not exhaust the idea of a free order.

It is useful to distinguish three related expressions without treating them as a universal progression or as perfectly closed categories:

• A legal state emphasizes that authorities act in accordance with the law.
• The rule of law adds requirements such as public and predictable rules, equality, a prohibition on arbitrariness, and access to independent justice.
• The constitutional rule of law places those requirements under a constitution of higher rank, which organizes public powers and protects rights through checks.

In setting out criteria for assessing the rule of law, the Venice Commission includes legality, legal certainty, the prohibition of arbitrariness, equality, human rights, and access to independent justice. The importance of that list is not that it supplies an exhaustive recipe, but that it reminds us that an enacted rule is not enough on its own.[^venice]

From a liberal perspective, the point is straightforward: general rules reduce the space for the personal will of those who govern. But a rule serves that function only if it also binds rulers and if someone can challenge its application.

The constitution as higher law

Constitutional supremacy means that the constitution does not stand on the same level as an ordinary statute. It may establish which bodies have authority, which procedures they must follow, and which limits a legislative majority or administrative authority may not cross.

Its binding force adds a practical element: those provisions must be usable as a standard in a dispute. In Marbury v. Madison (United States, 1803), the Supreme Court reasoned that where a higher written constitution conflicts with an incompatible statute, the constitution must govern. This is a historical illustration of one form of judicial review, not the universal origin or mandatory model for every legal system.[^marbury]

This distinction requires separating two planes. The formal constitution is the text, with its hierarchy and clauses. The effective constitution is the set of practices that makes those clauses real: authorities that respect their powers, courts able to decide independently, and decisions that are carried out. The first can exist without the second.

Warning: A supremacy clause can be symbolic if accessible remedies, independent judges, and compliance with decisions are absent.

Declared rights and working guarantees

A right and its guarantee are not the same thing. A right identifies a freedom, a protection, or a person's position in relation to power. A guarantee is the mechanism that helps make it enforceable: a procedure, a duty to give reasons, an appeal, a hearing, an impartial judge, or enforcement of a judgment.

The distinction matters when an authority restricts a freedom by invoking a broad public-interest rationale. It is not enough to read the catalogue of rights; one must ask who reviews the restriction, under what procedure, what defense the affected person may present, and what happens if the authority was wrong. Constitutional guarantees turn those questions into institutional avenues, although their specific scope varies from country to country.

Due process is part of that architecture. Requiring a competent authority, known rules, an opportunity to be heard, and a reviewable decision does not ensure a perfect outcome. It does prevent—or at least make more difficult—state coercion that rests simply on whim, political pressure, or the convenience of the moment.

Checks: necessary, but not magic

For a constitution to operate as a limit, power cannot concentrate the creation, execution, and review of its own decisions without counterweights. The separation of powers and other mechanisms of oversight distribute functions so that one authority is not at once the sole interested party and the sole judge of its own conduct.

Constitutional review takes different institutional forms. In some systems, a specialized court intervenes; in others, a supreme court or judges hearing particular cases do so. No institution is universally indispensable. What matters is that there be some institutional possibility of comparing a statute or public act with the higher law when the legal order provides for it.[^venice]

That review also raises a legitimate tension. When unelected judges set aside a measure approved by a majority, one may ask how much room remains for democratic self-government. The answer is neither to portray judges as infallible guardians nor to leave guarantees at the mercy of every majority. It requires defined powers, public procedures, reviewable reasons, and independence from political parties.

Key idea: Democracy decides who exercises power; constitutionalism also asks what that power may decide and under what rules.

Liberal constitutionalism emphasizes this second problem: a decision's legitimacy does not come solely from the number of votes behind it, but also from respect for rights, powers, and limits established in advance.

A majority-backed law can conflict with the constitution

Imagine that parliament passes, by a broad majority and through the ordinary procedure, a law that prohibits criticism of public officials and eliminates the possibility of appealing sanctions imposed under that prohibition. The law may have been formally valid in its enactment. Even so, in a constitutional rule-of-law system, at least two further questions arise: did the legislature have authority to restrict freedom of expression in that way, and was an effective remedy preserved for the sanctioned person?

If the constitution protects that freedom and requires a defense against state action, the majority does not by itself make the restriction constitutional. A competent reviewing body could examine it and, depending on the applicable institutional design, prevent its enforcement or hold it incompatible with higher law. The example does not show that every restriction is invalid; it shows why legislative procedure is not the only relevant criterion.

Design does not replace compliance

The constitutional rule of law is not a promise that conflicts will disappear or that every judicial decision will protect liberty. A constitution may be generous on paper while public authorities are unwilling to respect it. Checks may also be poorly designed, slow, or captured by political interests.

Its contribution is to offer a demanding standard: power must justify its decisions within higher rules, respect rights, and accept checks it does not fully control. When a majority-backed law encroaches on a constitutional guarantee, the question is no longer only what the majority wanted. It becomes whether power has remained within the limits that make government compatible with the liberty of those subject to it.

[^venice]: Venice Commission, Council of Europe, *Rule of Law Checklist* (2016), pp. 11–12 and 47. [^marbury]: Supreme Court of the United States, *Marbury v. Madison*, 5 U.S. 137 (1803), pp. 176–178 of the report.