Definition
The partial alteration or modification of an existing law by the passage of a new law inconsistent with it. Obrogation operates by implication: the newer enactment does not expressly repeal the earlier law but contradicts or supersedes it in part, leaving the remainder of the original law intact.
Obrogation is a concept drawn from Roman and civil law that describes one mechanism by which legislation can be changed without formal repeal. It stands in contrast to abrogation, which is the complete annulment of a law.
Common Confusion
OBROGATION vs. ABROGATION vs. DEROGATION vs. SUBROGATION: These four terms share a Latin root and appear in close proximity in historical legal dictionaries, creating persistent confusion.
- Abrogation: the complete repeal or annulment of a law.
- Obrogation: the partial alteration of a law by an inconsistent later enactment.
- Derogation: the partial repeal or limiting of a law, typically by explicit provision rather than inconsistency.
- Subrogation: an entirely unrelated doctrine in modern law concerning the substitution of one party for another in the context of rights or obligations.
Researchers should be particularly cautious with obrogation and derogation, which are frequently treated as synonyms in older sources despite the technical distinction maintained in civil law texts.
Why It Matters in Research
Obrogation is primarily a term of art in civil law systems and in historical English legal scholarship influenced by Roman law. It rarely appears in modern American common law opinions or statutes, which instead use the language of implied repeal or supersession. Researchers encountering obrogation in historical materials should understand they are reading a civilian or scholarly register, not a term of everyday judicial practice.
The key research trap is assuming obrogation maps directly onto the modern common law doctrine of implied repeal. The concepts overlap but are not identical. In the civil law tradition, the taxonomy of abrogation, obrogation, derogation, and subrogation (in its legislative sense) was a formal and carefully maintained system. Common law courts and commentators borrowed these terms selectively and inconsistently, sometimes using obrogation to mean full repeal and sometimes using abrogation to mean only partial change.
Corpus researchers working in colonial-era or early American legal texts, or in materials derived from Louisiana, Quebec, or other mixed civil-common law jurisdictions, will encounter obrogation with greater frequency and with more technical precision than in general common law sources. In those contexts, the distinction between obrogation and derogation may carry genuine doctrinal weight.
Because the term has largely dropped out of modern American legal vocabulary, its absence from recent secondary sources should not be read as an indication that the underlying concept is irrelevant. The doctrine survives under the label of implied partial repeal, and researchers investigating legislative history questions may need to translate freely between the terminologies.
Historical Dictionary Support
The historical sources agree closely on the core definition. Black's (both editions), Rapalje & Lawrence, and Bouvier all define obrogation as the alteration of a law by the passage of a contrary or inconsistent law, citing Calvin's Lexicon Juridicum as the common authority. The consistency of this single-source citation across multiple dictionaries suggests that compilers were drawing from the same civilian reference tradition rather than from independent common law usage.
Bouvier's formulation is the most precise among the historical sources, distinguishing between annulment in whole or in part and identifying the mechanism as the passage of a contrary law. This is a useful distinction for researchers: Bouvier treats obrogation as capable of operating on the whole of a law (overlapping with abrogation) or on part of it (the more technically specific meaning), whereas Black's presents it more narrowly as partial alteration.
The fragment appearing in Black's (1st ed.) regarding "joint and several rights of the creditors parties to the obligation" is not part of the obrogation definition; it is a printing artifact from an adjacent entry and should be disregarded.
What the historical dictionaries do not supply is any illustration of obrogation in reported cases. The term appears in their pages as a learned borrowing from Roman law rather than as a term with living common law application, which accurately reflects its status in Anglo-American practice.
Jurisdictional Note
Obrogation carries more weight as a technical term in civil law jurisdictions, particularly Louisiana, where civilian legislative methodology has historically informed how courts reason about conflicts between statutes. In common law jurisdictions, the functional equivalent is implied partial repeal, and practitioners and judges will not typically use the term obrogation.