The case of Washington v. Texas was about whether the Sixth Amendment right to compulsory process for obtaining witnesses in a criminal case applies to the states through the Fourteenth Amendment. The case also questioned whether a state procedural statute that prohibits persons charged as principals, accomplices, or accessories in the same crime from being introduced as witnesses for each other violates this right. The Supreme Court decided that the Sixth Amendment right to compulsory process for obtaining witnesses in a criminal case applies to the states through the Fourteenth Amendment and that the state procedural statute violated this right. The defendant's conviction was based on the trial judge's refusal to allow a crucial witness to testify due to Texas statutes preventing co-participants from testifying for each other. The Court held that the defendant's right to compulsory process was violated when a state statute made the testimony of a witness inadmissible, regardless of whether they were present in court or not. The Sixth Amendment guarantees a defendant the right to put their witnesses on the stand and to compel their attendance in court, which is essential to a fair trial.

Common law had restrictions on witness testimony, but in 1918, the Supreme Court overruled this and stated that the truth is more likely to be arrived at by hearing the testimony of all persons of competent understanding. The Sixth Amendment requires the admissibility of defense testimony, and arbitrary rules that prevent whole categories of defense witnesses from testifying violate the Constitution. The rule disqualifying an alleged accomplice from testifying on behalf of the defendant is flawed and violates the defendant's right to obtain witnesses in his favor. The conviction is reversed. Justice Harlan concurs with the result but disagrees with the idea that the Due Process Clause incorporates the specific provisions of the Bill of Rights. He believes that the State's arbitrary bar on the use of relevant and competent testimony by the defendant violates the Due Process Clause.