Which aspect of American government illustrates interpretation of the Constitution through custom?

One key aspect of American government that illustrates the interpretation of the Constitution through custom is the practice of judicial review. Although not explicitly mentioned in the Constitution, the Supreme Court established this principle in the landmark case Marbury v. Madison (1803) and has since interpreted the Constitution through various rulings. Additionally, the two-party system, while not outlined in the Constitution, has become a longstanding custom that shapes political processes and governance in the United States. These practices exemplify how customs can influence the practical application of constitutional principles.