In Mattox v. United States (1894), the U.S Supreme Court ruled that a defendant's constitutional right to confront witnesses against him is not violated when a deceased witness's testimony from an earlier trial is used in a retrial. The case involved Rufus Mattox, who was convicted of murder based on two key testimonies. When one of those witnesses died before his appeal and second trial, the court allowed his previous testimony to be read to the jury. On appeal, Mattox argued this violated his Sixth Amendment right "to be confronted with the witnesses against him." However, the Supreme Court disagreed stating that while defendants have rights under confrontation clause of Sixth Amendment, these are not absolute and may give way under certain circumstances such as death of witness after first trial.

In the dissenting opinion for Mattox v. United States, Justice Brewer argued that the use of a deceased witness's testimony from an earlier trial violated the defendant's Sixth Amendment right to confront witnesses against him. He contended that this constitutional guarantee was not limited to just being physically present during testimony but also included cross-examination as a critical component of confrontation. The majority’s decision, according to Justice Brewer, undermined this fundamental principle by allowing previous testimonies without providing any opportunity for re-cross examination in light of new evidence or circumstances. Furthermore, he expressed concern about potential misuse and manipulation if such hearsay evidence were permitted routinely in courts.