Final answer:
The Fourteenth Amendment has been used to extend national constitutional guarantees to the states, as shown in Gideon v. Wainwright and Miranda v. Arizona cases, ensuring the right to counsel and protection against self-incrimination at the state level.
Step-by-step explanation:
Interpretation of the Fourteenth Amendment
The U.S. Supreme Court has interpreted the Fourteenth Amendment to extend many national constitutional guarantees to the states. This application is evidenced by landmark cases such as Gideon v. Wainwright and Miranda v. Arizona. In Gideon v. Wainwright (1963), the Supreme Court unanimously ruled that states are required to provide legal counsel to defendants who can't afford one, as part of their right to a fair trial under the Sixth Amendment, applied to the states by the Fourteenth Amendment. Similarly, in Miranda v. Arizona (1966), it was established that suspects must be informed of their Fifth Amendment right against self-incrimination and right to an attorney during police interrogations. These decisions underscore the importance of the Fourteenth Amendment in expanding the reach of rights protected by the federal constitution to include state actions.