Sosna v. Iowa, 419 U.S. 393 (1975) (U.S. Supreme Court)
Sosna v. Iowa occupies a distinctive place at the intersection of Civil Procedure and Constitutional Law.
1) Whether a class action challenging Iowa's one-year residency requirement for filing a divorce action became moot when the named plaintiff's personal claim became moot after class certification; and 2) Whether Iowa's one-year durational residency requirement for access to its divorce courts violates the Fourteenth Amendment by infringing the constitutional right to travel or denying equal protection and due process.
Article III mootness: In a properly certified class action, the case does not become moot when the named plaintiff's individual claim becomes moot after certification; the class acquires a legal status independent of the named plaintiff, and a live controversy persists so long as class members continue to be affected. Substantive constitutional law: A state may impose a reasonable durational residency requirement before allowing access to its divorce courts when the requirement serves legitimate and substantial state interests—such as establishing domicile to ensure jurisdiction, promoting the integrity and recognition of decrees under the Full Faith and Credit Clause, and deterring migratory divorces—without unconstitutionally burdening the right to travel or violating equal protection or due process.
1) The action was not moot despite the named plaintiff's personal claim becoming moot after class certification; the certified class continued to present a live controversy. 2) Iowa's one-year residency requirement for filing a divorce action is constitutional; it does not violate the Fourteenth Amendment or impermissibly burden the right to travel.
Sosna is a bedrock case for the mootness doctrine in class actions: once a class is certified, subsequent mootness of the named plaintiff's claim does not moot the class claims. It also provides a template for analyzing durational residency rules under the Fourteenth Amendment, marking a limit to the right-to-travel jurisprudence of Shapiro and Dunn and refining Boddie's access-to-courts rationale. For Civil Procedure, it underscores the procedural consequences of Rule 23 certification; for Constitutional Law, it illustrates judicial deference to state domestic-relations administration when reasonable and supported by substantial interests.