Final answer:
Defendants' statements during custodial interrogation are inadmissible in state and federal courts if not preceded by the issuance of Miranda rights, protecting against self-incrimination and ensuring the right to counsel.
Step-by-step explanation:
Admissibility of Statements During Custodial Interrogation
Statements made by defendants during custodial interrogation are inadmissible in state and federal courts if the defendants were not informed of their right to counsel and protection against self-incrimination as required under the Fifth Amendment.
The landmark case of Miranda v. Arizona established that suspects must be warned of their right to remain silent and to have an attorney present.
If these warnings are not provided, any statement or confession the suspect makes may be considered inadmissible because they have not been informed of their constitutional rights, which include the right against self-incrimination under the Fifth Amendment and the right to an attorney under the Sixth Amendment.
Further implications from cases such as Escobedo v. Illinois and Michigan v. Jackson highlight that once a person in custody has asserted their right to counsel, police interrogations must cease until an attorney is present.
The right to counsel is critical in ensuring that a suspect's statements are voluntary and not coerced. However, as stated in Montejo v. Louisiana, a defendant may waive their right to counsel during police interrogation under specific circumstances, even if they have previously asserted their right.