United States. v. Scheffer, 523 U.S. 303 (1998)

In April 1997, Edward Scheffer, an airman in the United States Air Force, failed to appear to work, could not be located on base, and was declared absent without leave from the service. During a routine traffic stop, an Iowa state police officer identified Scheffer and placed him under arrest, holding him until he could be returned to the base. A urine analysis revealed the presence of methamphet-amines. Scheffer sought to introduce polygraph results during his general court-martial, which indicated he had not lied when denying drug charges and use while in the service. However, Military Rules of Evidence, specifically Rule 707, prohibit the use of polygraph results in court-martial proceedings. The Supreme Court granted certiorari to determine whether the exclusion of polygraph results violated the defendant’s Sixth Amendment right to present a fair defense.
The Court determined that state and federal authorities have a legitimate interest in the admission of only reliable evidence at trial. The impression given by the Court was that polygraph evidence has poor reliability and that even advocates of such tests admit the existence of erroneous results. While the defendant has the right to present relevant evidence, that evidence is subject to reasonable restrictions. Courts can make rules restricting admission of evidence as long as they are not arbitrary or disproportionate to the purposes served. In the Court’s eyes, Rule 707 creates a balance, excluding both favorable and unfavorable results. Exclusion of unreliable evidence is a principal objective of evidentiary rules. Finally, the Court determined that the ultimate determination of truth and credibility lies, and should remain, in the hands of juries and not machines. A fundamental premise of the American criminal trial system is that the jury determines credibility. In essence, the jury serves as its own lie detector. Polygraphs diminish the jury’s role, and unlike fingerprints, which are solid evidence and fact, a polygraph is another opinion as to whether a witness or defendant is telling the truth. See also: Automobile; Sobriety checkpoint