INTERVENTION - The Law Mind Legal Dictionary

INTERVENTIONAuthored

The Law Mind • 1330 words

Definition

Intervention is the procedural mechanism by which a person or entity not originally named as a party to a lawsuit inserts itself into the proceeding because it holds an interest in the subject matter or outcome of the litigation. The intervenor becomes a party — either alongside an existing party or in opposition — and may assert claims or defenses of its own.

The term carries distinct meanings across legal contexts:

1. CIVIL PROCEDURE (domestic). The formal process by which a third party obtains leave to join pending litigation. The intervenor must generally show either a right to intervene (because existing parties cannot adequately protect its interest, or because a statute confers the right) or permissive grounds (where its claim shares a common question of law or fact with the main action). Courts evaluate whether the intervention is timely and whether the proposed intervenor's interest is direct, substantial, and legally protectable.

2. INTERNATIONAL LAW. The act by which one sovereign state inserts itself into the affairs of another — through diplomacy, economic pressure, or force — without the latter's consent. This usage is categorically different from the procedural sense and carries its own body of doctrine under public international law.

3. CIVIL LAW TRADITION. Derived from Roman and civilian procedure, intervention historically described the act of a third party "coming between" litigants to assert a claim in the pending proceeding. This is the conceptual ancestor of the modern domestic procedural right.

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Common Language

Modern common usage (Wiktionary): The action of intervening or interfering in some course of events; also, in informal contemporary usage, an organized effort by family or friends to persuade someone with an addiction to seek help.

Historical common usage (Webster's 1913): "The act of intervening; interposition... Any interference that may affect the interests of others; especially, of one or more states with the affairs of another."

The gap matters. In ordinary language, intervention suggests uninvited interference — often carrying a negative or at least neutral connotation. In civil procedure, it is a formal, court-sanctioned mechanism: a party exercises a right or seeks permission. The process is regulated, not spontaneous. Researchers encountering "intervention" in historical legal sources must read context carefully to determine whether the author means the procedural device, the international-law concept, or simply the general English sense of interposition.

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Common Confusion

INTERVENTION vs. INTERPLEADER: Both involve a third party and a pending proceeding, but they operate differently. An intervenor asserts its own claim to participate in existing litigation. In interpleader, a stakeholder holding property disputed by multiple claimants forces those claimants into court to settle among themselves — the stakeholder is typically trying to exit the dispute, not join it.

INTERVENTION (civil procedure) vs. INTERVENTION (international law): These share a word and a general concept of one party inserting itself between others, but they are governed by entirely separate bodies of law and appear in entirely different source materials. Conflating them in historical research — particularly when reading early treatises that move between domestic and international contexts without clean transitions — is a genuine hazard.

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Recognized Forms

/SUBTYPES

INTERVENTION OF RIGHT: The intervenor has a legally recognized entitlement to participate, typically because disposition of the action without it may impair its interest and existing parties do not adequately represent that interest. Statutes may also expressly confer the right.

PERMISSIVE INTERVENTION: The court has discretion to allow a third party to intervene when its claim or defense shares a common question of law or fact with the main proceeding. Courts weigh delay, prejudice to existing parties, and judicial economy.

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Why It Matters in Research

The historical dictionaries in the Law Mind corpus are inconsistent in their coverage of intervention, and researchers should approach them with that limitation in mind.

Burrill provides the most useful baseline for the civil-law and procedural sense, explicitly noting that "intervention is unknown in the English common law" — a critical observation. This means researchers working with pre-twentieth-century English cases and treatises will find the procedural concept largely absent, while civilian and equity-adjacent sources may engage it more readily. The concept entered American federal practice through the equity rules and was later codified in the Federal Rules of Civil Procedure; its shape changed materially at each transition.

Black's (1st Ed.) entry as reproduced here addresses the international-law sense almost exclusively. Researchers who rely on Black's alone for historical guidance may miss the procedural dimension entirely or misread its boundaries. The 2nd Ed. excerpt in the source material is clearly a misattributed passage (it describes the Interstate Commerce Commission), which is itself a reminder that historical dictionary reprints can contain indexing or OCR errors that misdirect research.

Rapalje & Lawrence's fragment references intestate succession terminology — again almost certainly a neighboring-entry bleed-through — and provides no usable content on intervention itself.

The civil-law lineage matters for understanding how courts in Louisiana, and to a lesser extent other jurisdictions with civilian influence, conceptualize intervention differently from federal practice or common-law states. Researchers working across jurisdictional lines should not assume that procedural rules governing timeliness, the nature of the required interest, or the intervenor's rights on appeal transfer cleanly.

For constitutional research, intervention intersects with standing doctrine: a proposed intervenor must typically demonstrate the same injury-in-fact and redressability that Article III requires of original parties, though the precise relationship between intervention standards and constitutional standing remains a site of ongoing judicial development.

The encyclopedia entry on parental rights and state intervention addresses a substantive-law use of the term — state intervention into family relationships — that is distinct from both the procedural and international-law senses. Researchers should not conflate that usage with the procedural mechanism.

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Historical Dictionary Support

Burrill offers the most substantive historical treatment among the shelf sources, correctly tracing the term to the Latin interventio and situating it within the civilian tradition as "the act by which a person, not originally a party to a suit or proceeding, but claiming an interest in the subject matter in dispute, interposes his claim." His note that the concept was "unknown in the English common law" is historically accurate and important: common-law courts historically resolved third-party claims through separate actions, not through formal joinder mechanisms of this kind.

Black's (1st Ed.) pivot to international law is not wrong — the term had robust meaning in that domain throughout the nineteenth century — but the coverage is incomplete for researchers interested in the procedural device. The definition trails off before articulating the distinction between intervention and mediation cleanly, though the opening clause suggests Black's understood the difference: intervention might result in force; mediation is by nature pacific.

None of the historical dictionaries adequately address the evolution of intervention in American federal practice, the development of the right-versus-permissive distinction, or the relationship between intervention and constitutional standing. Researchers working with modern doctrine will need to move well beyond the shelf sources.

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Jurisdictional Note

In federal practice, intervention is governed by the Federal Rules of Civil Procedure, which draw a formal distinction between intervention of right and permissive intervention. State procedural rules vary considerably; some follow the federal model closely, others impose different interest requirements or timeliness standards. Louisiana's civilian tradition gives intervention a somewhat different conceptual foundation and procedural texture than common-law states. International-law intervention operates entirely outside domestic procedural frameworks and is governed by treaty, custom, and public international law doctrine.

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Encyclopedia Cross-Reference

Parental Rights — Education, Custody, and State Intervention (Law Mind Constitutional Law Encyclopedia) — addresses the substantive constitutional dimension of state intervention into family relationships, distinct from the procedural mechanism defined here.

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INTERVENTIONmain

Black's Law Dictionary • 1891

In international law. Intervention is such an interference between two or more states as may (accord- ing to the event) result in a resort to force; while mediation always is, and is intended to

INTERVENTIONmain

Black's Law Dictionary (2nd Ed.) • 1910

pooling of freights, etc., requiring schedules of rates to be published, establishing a commission to carry out the measures enacted, and prescribing the powers and duties of such commission and the procedure before it—Interstate commerce commission. A commission created by the interstate commerce act (q. v.) to ca out the measures therein enacted, composed of five persons, appointed by the President, empowered to inquire into the business of the carriers affected, to enforce the law, to receive, investigate, and determine complaints made to them of any violation of the act, make annual reports, hold stated sessions, etc.—Interstate extradi~ tion. The reclamation and surrender, according to due legal proceedings, of a person who, having committed a crime in one of the states of the Union, has fied into another state to evade justice or escape prosecution.—Inter= state law. That branch of private international law which affords rules and principles for the determination of controversies between citizens of different states in respect to mutual rights or obligations, in eo far as the same are affected by the diversity of their citizenship or by diversity in the laws or institutions of the several states. In international law. Intervention is such an interference between two or more states as may (according to the event) result in a resort to force; while mediation always is, and is intended to be and to continue, peaceful only. Intervention between a sovereign and his own subjects {s not justified by anything in international law; but a remonstrance may. be addressed to the sovereign in a proper case. Brown. In English ecclesiastical law. The proceeding of a third person, who, not being originally a party to the suit or proceeding, but claiming an interest in the subject-matter in dispute, in order the better to protect such interest, interposes his claim. 2 Chit Pr. 492; 3 Chit. Commer. Law, 633; 2 Hagg. Const. 137; 3 Phillim. Ecc. Law, 586. In the civil law. The act by which a third party demands to be received as a . party in a suit pending between other persons. The intervention is made either for the purpose of being joined to the plaintiff, and to claim the same thing he does, or some other thing eonnected with it; or to join the defendant, and with him to oppose the claim of the plaintiff, which it is his interest to defeat. Poth. Proc. Civile, pt. 1, c 2, § 7%, no. 8. In practice. A proceeding in a suit or ac tion by which a third person is permitted by the court to make himself a party, either joining the plaintiff in claiming what is sought by the complaint, or uniting with the defendant in resisting the claims of the plainINTESTABILIS: tiff, or demanding something adversely to both of them. Logan v. Greenlaw (C. C.) 12 Fed. 16; Fischer v. Hanna, 8 Colo. App. 471, 47 Pac. 3083; Gale v. Frazier, 4 Dak. 196, 30 N. W. 138; Reay v. Butler (Cal.) 7 Pac. 671.

INTERVENTIONmain

Rapalje & Lawrence • 1888

In international made one not legally valid; or if the testament he has made be revoked, or made useless; or if no one becomes heir under it. INTICING, (a servant to leave his master). 6 Mod. 101.

INTERVENTIONn.

Websters Unabridged Dictionary (1913) • 1913

The act of intervening; interposition. Sound is shut out by the intervention of that lax membrane. Holder. Any interference that may affect the interests of others; especially, of one or more states with the affairs of another; mediation. Let us decide our quarrels at home, without the intervention, of any foreign power. Sir W. Temple. The act by which a third person, to protect his own interest, interposes and becomes a party to a suit pending between other parties.

interventionnoun

Wiktionary (English) • 2026

Wiktionary contributors • CC BY-SA 4.0 • via Kaikki
Extracted and formatted for display by Law Mind. Source link opens the current Wiktionary page and its contributor history; it is not a frozen copy of this extract.

The action of intervening; interfering in some course of events. | A legal motion through which a person or entity who has not been named as a party to a case seeks to have the court order that they be made a party. | An orchestrated attempt to convince somebody with an addiction or other psychological problem to seek professional help and/or change their behavior. | An action taken or procedure performed; an operation.

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