What does nulla poena sine lege mean?
The Latin maxim nullum crimen, nulla poena sine lege means "no crime, no punishment without law." The idea, popularized by the German jurist Anselm von Feuerbach in the early 1800s, is that the state can punish only conduct that a law clearly defined as criminal, with a penalty set in advance. Korean scholars call it 죄형법정주의, the "principle of statutory crimes and punishments."
- Core rule
- Crimes and penalties must be fixed by law before the act
- Who writes the law
- The legislature, not prosecutors, judges or custom
- Protects
- Individual liberty against arbitrary punishment
- Related ideas
- Rule of law, due process, separation of powers
The principle answers a basic fairness question: how can people obey the law if they can't know in advance what it forbids? It also limits power. If officials could punish whatever they disliked after the fact, criminal law would become a tool of control rather than a set of public rules. That's why the principle sits at the heart of the rule of law.
Where it appears in Korean law
Korea's Constitution provides that no one shall be punished except as provided by law and through lawful procedure (art. 12(1)), and that no citizen shall be prosecuted for an act that did not constitute a crime under the law in force when it was committed (art. 13(1)). The Criminal Act repeats the point: whether an act is a crime and how it's punished are determined by the law at the time of the act (art. 1(1)).
There's an important exception in the defendant's favor. If the law changes after the act so that the conduct is no longer a crime, or the penalty becomes lighter, the new law applies (Criminal Act art. 1(2)). The ban on retroactivity runs only one way.
The five corollaries
Textbooks usually break the principle into five sub-rules, and exam questions often ask students to discuss each one.
- Statutory requirement (법률주의): crimes must be defined by statutes passed by the legislature. Customary criminal law is excluded, and delegating the definition of crimes to executive rules is allowed only within narrow, specific limits.
- Ban on retroactivity (소급효금지): a law can't punish conduct that was lawful when done, or increase the punishment after the fact.
- Clarity (명확성): criminal statutes must be clear enough that an ordinary person can tell what's forbidden.
- Ban on analogy (유추해석금지): courts can't extend a criminal statute by analogy to similar conduct it doesn't cover.
- Appropriateness (적정성): the definition of crimes and the severity of penalties must be reasonable and proportionate.
Each corollary blocks a different shortcut to punishment. Together they make sure the only road to a criminal conviction runs through a clear law written in advance.
The statutory requirement links to the constitutional ban on blanket delegation (포괄위임금지, Constitution art. 75): when a criminal statute leaves details to a presidential decree, the statute itself must set out the essential elements and the range of punishment. The Constitutional Court has struck down penalty provisions that left the core of the crime to lower regulations. A case study on delegated legislation and this principle is Overseas Financial Account Reporting and the Limits of Delegated Legislation: A Case Note on Korean Supreme Court 2019Do11381.
Hard questions: retroactivity and analogy in practice
The ban on retroactivity covers punishment, but what counts as punishment? Korea's Constitutional Court treated the electronic monitoring order for sex offenders as a security measure rather than a criminal penalty, and in 2012 upheld applying it to people sentenced before the law took effect. Critics argue that an ankle monitor feels like punishment to the person wearing it. The statute of limitations raises a similar issue: extending a limitations period that hasn't yet expired is generally treated as permissible.
Changes in court precedent are another hard case. Korean courts have held that applying a new, harsher interpretation to earlier conduct doesn't violate the ban on retroactivity, because precedent isn't statute. The U.S. takes a different angle through due process, discussed in the next section.
Analogy is banned, but interpretation is not, and the line between them is contested. Interpreting a word according to its ordinary meaning and the statute's purpose is allowed; stretching it beyond the possible meaning of the words to reach conduct the legislature didn't cover is not. A course essay that works through customary law, retroactivity and analogy, and the weaknesses of each, is The Principle of Legality in Korean Criminal Law: Ban on Customary Criminal Law, Non-Retroactivity, Ban on Analogy and Their Problems.
The U.S. version: ex post facto laws, vagueness and lenity
The U.S. Constitution forbids both Congress and the states from passing ex post facto laws (Art. I, § 9, cl. 3 and § 10, cl. 1). In Calder v. Bull (1798), Justice Chase described four categories: laws that criminalize past innocent conduct, aggravate a past crime, increase its punishment, or change the rules of evidence to make conviction easier. The clauses apply only to criminal laws, not civil ones.
Clarity comes through the void-for-vagueness doctrine under the Due Process Clauses. A statute is void if people "of common intelligence must necessarily guess at its meaning" (Connally v. General Construction Co., 1926). In Johnson v. United States (2015), the Supreme Court struck down the residual clause of the Armed Career Criminal Act as unconstitutionally vague.
The ban on analogy has a softer cousin, the rule of lenity: when a criminal statute is genuinely ambiguous after ordinary interpretation, courts resolve the doubt in the defendant's favor (United States v. Bass, 1971). And in Bouie v. City of Columbia (1964), the Court held that an unforeseeable judicial expansion of a criminal statute, applied retroactively, violates due process, though Rogers v. Tennessee (2001) later gave courts more room to change common-law doctrines.
- Calder v. Bull (1798)
- Defined the four categories of ex post facto laws
- Johnson v. United States (2015)
- Struck down the ACCA residual clause as void for vagueness
- Bouie v. City of Columbia (1964)
- Unforeseeable retroactive judicial expansion of a crime violates due process
Korea vs. the U.S.: same goal, different tools
| Korea | United States | |
|---|---|---|
| Retroactivity | Constitution art. 13(1); Criminal Act art. 1 | Ex Post Facto Clauses |
| Clarity | Clarity principle, Constitutional Court review | Void-for-vagueness doctrine |
| Extension by courts | Strict ban on analogy | Rule of lenity; Bouie due process limit |
| Customary crimes | Excluded | Federal common-law crimes rejected (United States v. Hudson & Goodwin, 1812) |
Both systems rest on the same idea: punishment is the state's most serious power, so it must be exercised only through rules everyone could know in advance. The principle also shapes procedure. A complaint filed under the criminal complaint process can lead to charges only if the conduct fits an offense that existed when it happened, and trials follow the protections described in criminal procedure.
A law written after the fact isn't really a rule; it's a verdict dressed up as one. Nulla poena sine lege insists that the rule must come first.
- What is nulla poena sine lege in simple terms?
- It means you can't be punished for something unless a clear law already made it a crime, with a set penalty, when you did it.
- What are the corollaries of the principle of legality?
- Korean textbooks list five: statutory requirement, ban on retroactivity, clarity, ban on analogy, and appropriateness of penalties.
- Can a new law apply to past conduct if it helps the defendant?
- Yes. In Korea, if a later law decriminalizes the conduct or lightens the penalty, the new law applies.
- How does the U.S. protect the same idea?
- Through the Ex Post Facto Clauses, the void-for-vagueness doctrine and the rule of lenity.