In the case of Cardona v. Power et al., 1965, the U.S Supreme Court was asked to consider whether New York's requirement that voters read and write English violated the Equal Protection Clause of the Fourteenth Amendment. The plaintiff, a Puerto Rican citizen who could not read or write in English but could do so in Spanish, argued that this law discriminated against him based on his national origin. However, the court ruled against him stating that literacy tests were not inherently discriminatory as they applied equally to all citizens regardless of their nationality or first language. Furthermore, it held that states have a legitimate interest in ensuring voters can understand ballot measures and candidate platforms which are typically presented in English.

In the dissenting opinion for Cardona v. Power et al., Justice Harlan argued that the case should not have been dismissed as moot, but rather decided on its merits. He believed that the Court's decision to dismiss was based on a misunderstanding of New York election law and an incorrect assumption about future events. According to him, there was no guarantee that the same issue would not arise again in subsequent elections, making it necessary for the Supreme Court to provide guidance by ruling on this case. Furthermore, he disagreed with majority’s interpretation of state law regarding voting rights and felt they had overstepped their jurisdiction by interpreting state laws instead of deferring to local courts' interpretations.