The district court correctly determined that subject matter and diversity of citizenship jurisdiction exists. Prot was domiciled in Texas when the state court action was commenced and when he removed the case to federal court. Although * * * [when the action was filed and then removed to federal court] Prot had physically moved himself, his family and his business to France, he had not formed an intention to remain there.
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What makes a person a citizen of a state? The fourteenth amendment to the Constitution provides that: “All persons born or naturalized in the United States, and subject to the jurisdiction thereof, are citizens of the United States and of the State wherein they reside.” However, “reside” has been interpreted to mean more than to be temporarily living in the state; it means to be “domiciled” there. Thus, to be a citizen of a state within the meaning of the diversity provision, a natural person must be both (1) a citizen of the United States, and (2) a domiciliary of that state. Federal common law, not the law of any state, determines whether a person is a citizen of a particular state for purposes of diversity jurisdiction.
Consistent with general principles for determining federal jurisdiction, diversity of citizenship must exist at the time the action is commenced. In cases removed from state court, diversity of citizenship must exist both at the time of filing in state court and at the time of removal to federal court. If diversity is established at the commencement and removal of the suit, it will not be destroyed by subsequent changes in the citizenship of the extant parties.