The Nottebohm case was brought before the International Court of Justice (ICJ) by Liechtenstein against Guatemala in 1951. Friedrich Nottebohm was a German national who had lived in Guatemala for many years. During World War II, he obtained Liechtenstein citizenship and later Guatemala, considering him an enemy alien, arrested and deported him to the United States, confiscating his property in Guatemala. Friedrich Nottebohm was considered an “enemy alien” by Guatemala during World War II because of his German nationality. At the time, Guatemala was aligned with the Allied Powers, and Germany was an enemy state. Although Nottebohm later acquired Liechtenstein nationality, Guatemala still treated him as a German national because it considered his ties to Germany stronger than his newly acquired citizenship. During World War II, Liechtenstein remained neutral. As a small landlocked country bordered by Switzerland and Austria, Liechtenstein followed a policy similar to that of Switzerland, avoiding involvement in the conflict. Liechtenstein sought to protect Nottebohm under international law, claiming Guatemala had violated its rights by not recognising his Liechtenstein nationality.

• 1. Whether Guatemala was obligated to recognise Nottebohm’s nationality acquired from Liechtenstein for the purposes of international law.
• 2. Whether the naturalisation of Nottebohm by Liechtenstein had created a genuine legal bond between him and Liechtenstein for the purposes of diplomatic protection.

The court noted that international law requires a genuine and effective connection between an individual and the state granting nationality. It emphasised that nationality must reflect a real social attachment, such as long-term residence, family ties, and economic interests. The court observed that Nottebohm had no genuine connection to Liechtenstein beyond the formal process of acquiring citizenship. He had continued to live and do business in Guatemala, with minimal ties to Liechtenstein.

The ICJ ruled in favour of Guatemala, concluding that Nottebohm’s naturalisation in Liechtenstein was not sufficient to obligate Guatemala to recognise it for the purposes of diplomatic protection. Liechtenstein’s claim on Nottebohm’s behalf was therefore rejected. The court held that for diplomatic protection to be claimed, there must be a genuine link between the individual and the state granting nationality.

The Nottebohm case established the “genuine link” principle in international law regarding nationality and diplomatic protection. This decision emphasised that states cannot use nationality as a mere formality to extend diplomatic protection; the individual must demonstrate a substantial and effective connection with the state. This case continues to influence discussions around dual nationality and the criteria for diplomatic protection under international law.