In the case of Hall et ux. v. Beals, Clerk and Recorder of El Paso County, et al., 1969, the U.S Supreme Court ruled on a Colorado law that required voters to have resided in the state for at least six months before they could vote in any election. The plaintiffs were residents who had moved to Colorado less than six months prior to an upcoming presidential election and argued that this residency requirement violated their constitutional rights under the Equal Protection Clause of the Fourteenth Amendment. However, by a 5-3 decision, with Justice Thurgood Marshall abstaining from voting due to his recent appointment as Solicitor General when this case was being heard in lower courts; it was held that these requirements did not violate equal protection principles because they served legitimate state interests such as preventing voter fraud and ensuring informed voting.

In the dissenting opinion for Hall et ux. v. Beals, Clerk and Recorder of El Paso County, et al., Justice William O. Douglas argued that Colorado's 6-month residency requirement to vote in a presidential election was unconstitutional as it violated the Equal Protection Clause of the Fourteenth Amendment. He believed that such requirements were arbitrary and served no compelling state interest; they only disenfranchised citizens who had recently moved to the state but were otherwise eligible voters under federal law. Furthermore, he emphasized that voting is a fundamental right protected by the Constitution and should not be restricted without substantial justification.