In Perez v. Brownell, the U.S. Supreme Court ruled in 1958 that a natural-born citizen of the United States could lose their citizenship by voting in a foreign election. Clemente Martinez Perez, who was born in El Paso, Texas and moved to Mexico with his parents when he was five years old, voted in Mexican elections on two occasions as an adult while still maintaining his American citizenship. The Attorney General sought to strip him of his US citizenship under Section 401(e) of the Nationality Act of 1940 which stated that any US citizen who votes in a political election within another country would lose their nationality status. In a split decision (5-4), the court upheld this provision and affirmed that Congress had power over establishing rules for expatriation.

In the dissenting opinion for Perez v. Brownell, Justice Hugo Black argued that citizenship is not a license that expires upon misbehavior. He contended that the deprivation of citizenship is not a weapon to be used by Congress in enforcing its views of policy against citizens who disagree with those views. Furthermore, he stated that such punishment leads to statelessness and violates principles of liberty and justice deeply embedded in traditional American law. He also emphasized his belief in an individual's right to travel as part of their personal liberty protected by the Constitution, which should not be taken away without due process or proof beyond reasonable doubt - standards he believed were not met in this case.