Which constitutional amendment was primarily focused on in both Plessy v. Ferguson and Brown v. Board of Education?

The correct answer is the Fourteenth Amendment, as it is fundamentally concerned with issues of equality under the law and has been pivotal in several landmark Supreme Court cases, including Plessy v. Ferguson and Brown v. Board of Education.

In Plessy v. Ferguson (1896), the Court upheld the constitutionality of racial segregation under the "separate but equal" doctrine, which was interpreted as permissible under the Equal Protection Clause of the Fourteenth Amendment. This case solidified the legal basis for racial discrimination in the United States for decades.

In contrast, Brown v. Board of Education (1954) directly challenged and ultimately overturned the principles established in Plessy. This case declared that state laws establishing separate public schools for black and white students were unconstitutional, as they violated the Equal Protection Clause of the Fourteenth Amendment by suggesting that separate educational facilities are inherently unequal.

Thus, both cases revolve around the interpretation and application of the Fourteenth Amendment, emphasizing its role in protecting civil rights and ensuring equal treatment under the law.