Fundamentals

Legal Certainty and Liberalism: What It Is and Why It Protects Freedom

By Daniel Sardá · Published on September 19, 2026

7 min read1,352 words

Legal certainty does not prevent laws from changing: it requires change to be public, understandable, and subject to limits that prevent arbitrariness.

Someone signing a contract, starting a business, or defending a right does not need to know in advance every decision a court will make. They do need to be able to find out which rules govern, what reasonable consequences their actions will have, and where to turn if an authority oversteps. That practical ability is at the heart of legal certainty.

From a liberal perspective, its value does not lie in making the legal order immutable. It lies in reducing people's dependence on unpredictable decisions. When rules are public, general, and subject to review, power has less room to turn a permit, fine, or exception into a personal favor or a selective punishment.

Key idea: Legal certainty does not mean absolute certainty about every dispute; it means being able to orient oneself by known rules and having safeguards against arbitrary decisions.

What legal certainty means

The expression is sometimes used as a synonym for peace of mind, but it does not refer to public safety or crime prevention. Public safety seeks to protect people from harm or violence. Legal certainty concerns the quality of the legal framework: rules should be accessible, sufficiently clear, and predictable in their application.

The Costa Rican Judiciary's Diccionario Usual links the concept to certainty, foreseeability, prior publication of rules, and changes made through legal procedures. It is a useful starting-point definition, with one important qualification: no legal system eliminates every doubt. Laws contain terms that require interpretation, facts may be contested, and judges may disagree. The reasonable demand is that such uncertainty not depend on a shifting will that cannot be anticipated.

For that reason, legal certainty is not simply a matter of having a written law. An administration may cite a rule while applying it through secret or contradictory standards, or standards designed for one specific person. Legality understood as mere formal authorization is insufficient when equality, verifiable reasons, and the possibility of review are missing.

The conditions that make a rule foreseeable

There is no single, identical catalogue for every constitutional system, but rule-of-law standards commonly bring together several connected safeguards. The Venice Commission's Rule of Law Checklist includes, among others, legality, legal certainty, the prohibition of arbitrariness, access to justice, human rights, and equality.

For a non-specialist reader, those safeguards can be summarized as follows:

• Publication and accessibility: a rule cannot guide conduct if those required to follow it cannot reasonably know it.
• Sufficient clarity: not every provision can be mathematical, but it must offer criteria for distinguishing what is permitted from what is prohibited.
• Prospective application: a person should not be penalized or deprived of a right under a rule created after they acted, except for narrowly defined exceptions within the legal order itself.
• Equality and generality: like cases should receive like consideration; exceptions require a justification that can be examined.
• Independent review: there must be a real avenue to challenge decisions, request reasons, and correct abuses.

These elements work together. A published rule that is written in empty terms can leave too much latitude to the decision-maker. A clear standard applied retroactively frustrates the reliance of someone who acted under the rule then in force. And a decision that is well explained on paper loses force if no one can review it.

Key idea: Stability helps people plan, but legal certainty requires more: known rules, non-retroactive application, equality, and the possibility of review.

Two everyday situations

Consider an administrative penalty. If the authority publishes the requirements in advance, explains what evidence it considers, and allows an appeal, a person can adapt their conduct and defend themselves if they believe there has been an error. They may disagree with the outcome, but they are not entirely at the mercy of an official.

The contrast is an ad hoc exception: the same conduct is tolerated for some people, punished for others, and no one knows the standard until they receive notice. The problem is not only the severity of the measure. The citizen cannot organize their decisions or effectively challenge unequal treatment.

Something similar happens with a contract. The parties take on risks and can anticipate them under known rules concerning property, performance, and remedies for breach. If a later amendment retroactively alters the agreement's essential effects, calculating obligations becomes much harder. That does not show that every legal change is improper; it shows why changes should be public, general, and ordinarily prospective.

The legal certainty of property rights illustrates this function especially well. Property is not limited to holding a title: it allows people to use, transfer, invest, or plan. Those decisions require that their basic conditions not depend on discretionary intervention without rules or recourse.

Why it matters in a liberal reading

Classical liberalism has placed central importance on limited government because freedom depends not only on the ends power claims to pursue. It also depends on how that power is exercised. An individual, unpredictable command can interfere with a person even when it is presented as serving the general interest.

From this tradition, a general law has an institutional advantage: it allows people to know the framework before acting and requires the authority to explain why a case falls within it. It does not make every general rule good, nor does it by itself settle political disagreement. But it shifts the relationship away from obedience to a particular will and toward a government of laws, whose rules also bind those who govern.

Leonardo Sempértegui has connected classical liberalism with the rule of law and the judicial protection of freedom. This connection is best understood as an institutional interpretation, not as a single liberal doctrine. There are legitimate disagreements over which rights should be protected, which regulations are permissible, or how far the state should reach. The shared point is narrower: public decisions affecting the individual sphere should have a public basis, limits, and safeguards.

Key idea: From a liberal perspective, legal certainty protects freedom because it makes it harder for a public decision to rest on whim, favor, or an unsupported exception.

This also clarifies the difference between a general rule and discretion. An administration sometimes needs to assess particular circumstances: issuing a permit, responding to an emergency, or choosing among proportionate measures. Discretion can be legitimate when it is bounded by purposes, criteria, reasons, and review. It becomes state arbitrariness when those limits disappear and the authority can decide without reasons others can examine.

Foreseeability is not automatic justice

It is worth avoiding an overly quick conclusion: a stable rule can be unjust, discriminatory, or incompatible with fundamental rights. Foreseeability limits one kind of harm—uncertainty in the face of power—but it does not by itself answer what content a law should have.

That is why the rule of law is not reduced to obeying any enacted rule. The Venice Commission associates legal certainty with equality, human rights, access to justice, and the prohibition of arbitrariness. These requirements make it possible to assess both the form and the effects of public action.

Nor should legal certainty be confused with immobility. Laws can, and sometimes must, be reformed in response to new problems, demonstrated errors, or social change. A reform is more compatible with legal certainty when it is clearly announced, applies prospectively, uses general criteria, and leaves avenues of review open. Political disagreement over reform does not disappear; at least it is no longer settled through legal surprises or last-minute privileges.

A practical limit on power

Legal certainty is a discipline for institutions and a guide for people. It asks that the law be knowable before it is obeyed, that power give reasons before it imposes consequences, and that there be an authority capable of reviewing its excesses.

It does not promise that every decision will be just or that every controversy will have a simple answer. It offers something more concrete: an order in which contracts, projects, rights, and disagreements do not depend primarily on who holds power that day. That is why predictable, correctable rules applied with equality are an important condition of freedom.