In the United States v. Owens case of 1987, the Supreme Court ruled that a witness's memory loss about certain details does not automatically render them incompetent to testify. The case arose when Frank Owens, an inmate at a federal prison, was charged with assaulting another prisoner named Arthur Grayson. During trial, Grayson could not remember specific aspects of his previous identification of Owens due to injuries sustained in the assault but maintained that he remembered identifying him as his attacker immediately after the incident occurred. The defense argued this rendered him incompetent as a witness and moved for acquittal based on insufficient evidence; however, both motions were denied by lower courts. The Supreme Court upheld these decisions in an 8-1 ruling stating that while cross-examination is intended to expose potential inaccuracies or inconsistencies in testimony due to forgetfulness or confusion among other things it doesn't necessarily disqualify someone from testifying altogether if they can't recall every detail surrounding their statements or actions related to a crime.

In the dissenting opinion for United States v. Owens, Justice William J. Brennan Jr., joined by Justices Thurgood Marshall and John Paul Stevens, argued that the majority's decision undermined a defendant's Sixth Amendment right to confront witnesses against them. They contended that allowing testimony from a witness who could not remember certain details due to memory loss was fundamentally unfair because it denied the defense an opportunity to effectively cross-examine and challenge their credibility. The dissenters believed that this violated basic principles of fairness in criminal trials as well as constitutional protections for defendants' rights.