In Brown v. Board of Education (1954), the Supreme Court ruled that schools segregated by race were unconstitutional. In response, some states opposed to desegregation passed laws to prevent the desegregation of schools. However, the Supreme Court again ruled in Cooper v. Aaron (1958) that its 1954 decision was binding on all states, regardless of conflicting state laws. Which clause in the Constitution allowed the Supreme Court to make this 1958 ruling?