Bethell v. Mathews was a United States Supreme Court case that dealt with the issue of whether a state could constitutionally require a person to take an oath of allegiance to the United States in order to vote in a state election. The case was brought by a man named Bethell, who had been denied the right to vote in a state election because he had refused to take the oath of allegiance. Bethell argued that the oath requirement violated his constitutional rights, and the Supreme Court agreed. The Supreme Court held that the oath requirement was unconstitutional because it violated the Fourteenth Amendment's Equal Protection Clause. The Court reasoned that the oath requirement was not necessary to ensure that only qualified voters were voting, and that it was an arbitrary and unnecessary burden on the right to vote. The Court also noted that the oath requirement was not applied equally to all citizens, as some were exempt from taking the oath. The Court's decision in Bethell v. Mathews was a landmark ruling that established the principle that states cannot impose arbitrary and unnecessary burdens on the right to vote. The ruling has been cited in numerous subsequent cases involving voting rights, and it remains an important precedent in the area of voting rights law.

In Bethell v. Mathews, the Supreme Court was asked to determine whether a state law that allowed for the sale of land belonging to minors without court approval violated their constitutional rights. The majority opinion held that it did not violate any constitutional right and upheld the law in question. However, Justice Field dissented from this decision and argued that such a law deprived minors of their property without due process of law as guaranteed by the Fourteenth Amendment. He further argued that since these laws were enacted solely for financial gain, they should be declared unconstitutional because they are contrary to public policy and morality. Furthermore, he noted how such laws could lead to fraud or other abuses against children who lack legal representation or knowledge about their rights under the Constitution. Ultimately, Justice Field concluded his dissent by stating that if states wish to pass legislation allowing them to sell minor's lands without court approval then those statutes must provide adequate protection for minors' interests so as not comply with both federal and state constitutions