Nottebohm Case (Liechtenstein v. Guatemala)
International Court of Justice
1955 I.C.J. 4
Nottebohm, a German national who had lived and conducted extensive business in Guatemala since 1905, obtained Liechtenstein citizenship in 1939 through a brief naturalization visit, then returned to Guatemala; after being arrested, deported, and denied readmission to Guatemala amid wartime hostilities and having his property there confiscated, Liechtenstein sued Guatemala at the ICJ for reparations, and Guatemala contested the validity of Nottebohm's Liechtenstein nationality for purposes of the claim.
Whether a State's unilateral recognition of a person as its naturalized citizen automatically entitles the State to exercise protection over the citizen against acts by other States, and requires recognition by other States of the person's nationality.