Also known as: multiple obligations · inconsistent obligations · conflicting obligations · incompatible duties
Written by attorneys · grounded in primary & secondary sources — see below
A substantial risk that an existing party will face double, multiple, or conflicting duties arising from the same interest if an action proceeds without a nonparty who claims an interest in the subject matter.
Harbor Investments sued Harbor Brokerage over margin account liquidations. Meridian Bank held a perfected security interest in the same securities and any recovery. Without joining Meridian, a judgment allocating ownership and losses could force Harbor Brokerage to satisfy conflicting claims from both the fund and the bank on the identical collateral.
A parolee challenged parole guidelines on behalf of a class whose sentences had expired. The Commission argued that later class members could sue separately on the same guidelines, exposing the agency to inconsistent rulings about guideline validity and remedy scope.
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Firefighters obtained a consent decree altering promotion practices. A group of nonparty employees later sued, claiming the decree created inconsistent obligations for the city on hiring standards that could not be reconciled with the earlier judgment.
Taxpayers and citizens sued to bar members of Congress from reserve commissions. The government faced potential separate suits by individual reservists and by Congress members asserting conflicting duties under the incompatibility clause.
Joinder is required when a nonparty claims an interest in the subject of the action and the absence of that party creates a substantial risk that an existing party will face double, multiple, or inconsistent obligations. The risk must be concrete rather than speculative.
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The complete-relief prong focuses on whether the court can fully resolve the dispute among those already before it. The inconsistent-obligations prong instead protects existing parties from later conflicting duties that arise because a nonparty's interest was not adjudicated.
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Prior settlements can create the required risk when the same proprietary methods or configurations are at issue and a new judgment could reopen or contradict those settlements. The risk must be immediate and concrete, not merely theoretical.
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…rendered in the absence of a person may "leave. . . persons already parties subject to a substantial risk of incurring . . . inconsistent obligations. . . ."[^maj-4] Rule 19(b) sets forth the factors to be considered by a court in deciding whether to allow an action to proceed in the absence of an interested party.[^maj-5] Joinder as a…