Definition
Incompatibility is the legal condition in which two things, rights, offices, or relationships cannot coexist in the same person or entity at the same time without conflict. The term operates in at least two distinct legal contexts:
1. Incompatibility of Offices. Two public offices are incompatible when the simultaneous holding of both by one person would produce a conflict of duty, a constitutional violation, or an impermissible concentration of governmental power. Incompatibility may arise from the inherent nature of the offices themselves — as when one office requires oversight of the other — or may be imposed expressly by statute or constitutional provision. The consequence of accepting an incompatible office is typically the automatic vacation of the first.
2. Incompatibility as a Ground for Divorce. In modern family law, incompatibility — sometimes styled "irreconcilable differences" or "incompatibility of temperament" — is a no-fault ground for divorce recognized in many jurisdictions. It refers to a breakdown in the marital relationship of such a degree that cohabitation and the fulfillment of marital obligations are no longer reasonably possible. No showing of fault by either party is required.
Common Language
Modern common usage (Wiktionary): The quality or state of being incompatible; inconsistency; irreconcilability.
Historical common usage (Webster's 1913): The quality or state of being incompatible; inconsistency; irreconcilableness.
The common meaning is broad and non-technical — two things that simply do not go together. The legal meaning is narrower and consequential: in the office context, incompatibility triggers automatic legal effects (forfeiture, vacancy) regardless of whether the officeholder intends conflict. In the divorce context, "incompatibility" is a term of art that substitutes for fault-based grounds and carries specific procedural weight. A researcher who reads the term in its ordinary sense will miss both the structural automaticity of the office doctrine and the doctrinal history of no-fault divorce reform.
Recognized Forms
/SUBTYPES
Incompatibility of Offices (Constitutional or Inherent). Arises from the structural relationship between the offices — where one officer would be required to act in a supervisory, adversarial, or duplicative capacity relative to the other. No statutory text is needed; the conflict is implied from the nature of the duties.
Incompatibility of Offices (Statutory). Expressly declared by legislature or constitutional provision. The U.S. Constitution's Ineligibility Clause (Art. I, § 6) and its provisions on officers holding civil positions provide federal examples. State constitutions and statutes commonly extend the prohibition more broadly across state offices.
Incompatibility of Interests or Relations. Two legal relations cannot simultaneously vest in the same person as to the same subject matter — as Bouvier illustrates with the landlord-tenant relationship. A person cannot simultaneously be both landlord and tenant of the same premises in the same capacity; the relations are legally inconsistent.
Incompatibility as a Divorce Ground. A statutory no-fault ground treating the marriage relationship itself as the subject of the incompatibility. Distinguished from fault grounds (cruelty, adultery, desertion) in that it requires no wrongdoing by either party.
Why It Matters in Research
Researchers encounter this term across radically different bodies of law, and conflating its uses will derail analysis. A case about incompatibility of offices has nothing to do with divorce law, and vice versa — yet the same word appears in both without qualification in older treatises and digests.
In the office context, the historical sources indexed under INCOMPATIBILITY often blend constitutional provisions, common law principles, and local statutory rules without clearly distinguishing them. Bouvier's entry points to the U.S. Constitution but also to Pennsylvania and South Carolina reporters and New York practice reports — a mix that reflects genuine variation in how the doctrine was applied at the state level. Researchers should not assume that a finding of incompatibility in one state's cases translates directly to another, since the doctrine's triggers and effects differ by jurisdiction.
In the divorce context, "incompatibility" as a statutory ground is largely a post-1960s development tied to no-fault reform. Pre-reform sources will not use the term as a divorce ground; they may use it colloquially to describe a troubled marriage while the operative legal ground was cruelty or desertion. Searching historical case law for incompatibility-based divorce before the no-fault era will return little of direct doctrinal value.
The automatic-vacation rule for incompatible offices is a trap in historical research: courts sometimes differ on whether acceptance of the second office vacates the first ipso facto or merely creates grounds for removal. The answer often turns on the specific jurisdiction's treatment, and older authorities may not distinguish clearly between the two.
Corpus connections: Office-incompatibility questions intersect with separation-of-powers materials, public officer qualification disputes, and constitutional convention records. Divorce-incompatibility materials connect to no-fault reform statutes, legislative history of family law codes, and comparative family law sources.
Historical Dictionary Support
Bouvier's Law Dictionary defines incompatibility as "incapability of existing or being exercised together," and its examples are drawn from the office and legal-relations contexts — not divorce. This reflects the pre-no-fault era in which incompatibility as a family law term had not yet become a term of art. Bouvier's formulation is tight and useful for the office doctrine: the landlord-tenant illustration efficiently captures the category of incompatible legal relations. The reference to U.S. Const. art. 1, § 6 anchors the constitutional dimension of the office rule.
What Bouvier does not address is the normative question of what happens when incompatible offices are accepted — whether vacancy is automatic or requires further proceedings. That gap is characteristic of the dictionary's era and signals a need to go to the case reporters Bouvier cites for the procedural answer.
No other historical dictionary sources were provided for this entry. Researchers should consult additional treatises on public officers (such as Mechem's A Treatise on the Law of Public Offices and Officers) for fuller treatment of the office doctrine, and post-reform family law treatises for the divorce ground.
Jurisdictional Note
The incompatibility of offices doctrine varies substantially by state, with some jurisdictions treating acceptance of an incompatible office as an automatic vacation of the first and others requiring a formal proceeding. The divorce ground of incompatibility (or irreconcilable differences) exists in most U.S. states following no-fault reform but the precise statutory language, procedural requirements, and whether incompatibility must be contested differ by state code.