Earl Warren,
Washington v. Texas — Opinion of the Court
“ In light of the common-law history, and in view of the recognition in the Reid case that the Sixth Amendment was designed in part to make the testimony of a defendant's witnesses admissible on his behalf in court, it could hardly be argued that a State would not violate the clause if it made all defense testimony inadmissible as a matter of procedural law. It is difficult to see how the Constitution is any less violated by arbitrary rules that prevent whole categories of defense witnesses from testifying on the basis of a priori categories that presume them unworthy of belief. ”
