Definition
Lex ordinandi is a Latin maxim meaning, in substance, the law of the forum — that is, the procedural law of the court in which litigation is pending. It designates the body of rules that governs how proceedings are conducted, as distinguished from the substantive law that determines the parties' underlying rights. The term is used interchangeably with lex fori in its procedural sense, and its primary function is to identify which jurisdiction's procedural rules apply when a court is hearing a matter with foreign or multi-jurisdictional elements.
In private international law and conflict of laws analysis, the distinction between substantive and procedural rules carries significant practical weight: a court will generally apply its own lex ordinandi (its local rules of procedure, evidence, and remedy) even when it applies another jurisdiction's substantive law to resolve the merits of a dispute.
Common Confusion
Lex ordinandi is consistently equated with lex fori by historical dictionaries, and the two are functionally synonymous in most usage. The potential for confusion lies in the fact that lex fori is itself a term with both a narrow procedural sense (equivalent to lex ordinandi) and a broader sense encompassing all the law of the forum, including its substantive law. A researcher encountering lex ordinandi in a historical source should treat it as a signal that the author is invoking the procedural dimension of lex fori specifically, not the forum's substantive law. The companion term lex causae — the law governing the substance of the dispute — is the conceptual counterpart to lex ordinandi in conflict of laws analysis.
Why It Matters in Research
Lex ordinandi appears rarely in modern legal writing. It is primarily encountered in nineteenth-century treatises on conflict of laws, private international law, and civil procedure, where Latin maxims were the standard currency of doctrinal argument. Researchers working in those materials should understand that the term is not a distinct doctrine but a label for a well-established principle.
The more significant research challenge is the substantive/procedural distinction itself, which lex ordinandi sits at the heart of. Courts have historically drawn that line inconsistently — statutes of limitations, burden of proof, and rules of evidence have all migrated between "procedural" and "substantive" classifications depending on the court and era. What a historical source calls lex ordinandi may therefore cover a narrower or broader range of rules than a modern reader would expect.
When tracing conflict of laws doctrine in the Law Mind corpus, lex ordinandi most commonly surfaces alongside lex fori, lex loci, and lex causae. Rapalje & Lawrence's entry connects it loosely to two other maxims — lex plus laudatur quando ratione probatur (the law is more praised when supported by reason) and lex semper dabit remedium (the law will always give a remedy) — which, while not definitional, reflect the rhetorical environment in which the term appeared and suggest that historical authors sometimes grouped procedural-forum maxims thematically rather than systematically.
No independent doctrinal development attaches to lex ordinandi as a term. Researchers looking for substantive analysis should pivot immediately to lex fori and to the broader conflict of laws literature.
Historical Dictionary Support
Both Black's Law Dictionary and Rapalje & Lawrence define lex ordinandi identically and minimally: it is the same as lex fori. Neither source provides independent exposition of the term. Rapalje & Lawrence's entry is notable chiefly for embedding the definition within a cluster of unrelated Latin maxims, suggesting the term was treated as a cross-reference placeholder rather than a doctrine warranting its own treatment.
The brevity of these entries is itself informative. By the time these dictionaries were compiled, lex ordinandi had no independent analytical life — it was a synonym that appeared in older materials and required only a redirection. Historical sources predating these dictionaries, particularly treatises on international law and equity procedure, are where a researcher would need to look to find the term deployed substantively.
Jurisdictional Note
As a Latin maxim summarizing a general common law principle, lex ordinandi carries no jurisdiction-specific meaning. Variation in how courts apply the underlying principle — which rules count as procedural for choice-of-law purposes — is significant and jurisdiction-dependent, but that variation attaches to the doctrine, not the term.