Military courts handle polygraph results with a categorical rule of exclusion. In a court-martial, including an Article 120 sexual offense case, polygraph evidence is not admissible to prove guilt or innocence at trial, and the same prohibition shapes how such evidence is treated when it surfaces during pretrial motions. The governing rule is Military Rule of Evidence 707, and its constitutionality was upheld by the Supreme Court of the United States. Understanding the scope of that rule, and the narrow situations in which polygraph information can still matter procedurally, is essential for anyone litigating an Article 120 case.
The flat ban under MRE 707
Military Rule of Evidence 707 provides that, notwithstanding any other provision of law, the results of a polygraph examination, the opinion of a polygraph examiner, and any reference to an offer to take, a failure to take, or the taking of a polygraph examination are not admissible into evidence. This is a per se exclusion. It does not turn on the reliability of the particular examiner or the quality of a specific test. It sweeps in the chart results, the examiner’s opinion about deception, and even the mere fact that a polygraph was offered or taken.
The breadth of the rule matters in sexual-assault litigation, where parties on both sides sometimes try to use a favorable polygraph. An accused cannot introduce a “passed” polygraph to suggest innocence, and the government cannot introduce a “failed” polygraph or the accused’s refusal to take one. The rule applies evenhandedly.
The Supreme Court’s endorsement in Scheffer
The leading authority is United States v. Scheffer, 523 U.S. 303 (1998). There, an Air Force member sought to introduce favorable polygraph results to support his defense, and MRE 707 barred them. The Supreme Court held that the per se exclusion of polygraph evidence under MRE 707 does not unconstitutionally abridge the accused’s Sixth Amendment right to present a defense. The Court reasoned that there is no consensus that polygraph evidence is reliable and that the government has legitimate interests in barring unreliable evidence and in preserving the members’ role in judging credibility. Scheffer remains the foundation for the military’s treatment of polygraphs.
How this plays out during Article 120 pretrial motions
Pretrial motions are where polygraph issues most often arise, and the analysis tracks the same exclusion. Several recurring scenarios illustrate it.
First, a party may move in limine to admit or exclude polygraph evidence. Given MRE 707, a defense motion to admit a favorable examination will be denied, and a government effort to use a polygraph against the accused will likewise be barred. The military judge applies the rule directly.
Second, polygraph references can contaminate other evidence. A confession is sometimes obtained during or right after a polygraph session, when an examiner confronts the suspect with the supposed results. The polygraph results themselves stay out under MRE 707, but the confession may still be admissible if it was voluntary and properly obtained. During a pretrial suppression motion, the defense can argue that the polygraph procedure rendered the statement involuntary or that the Article 31 and Fifth Amendment requirements were not met. The judge can hear about the polygraph context for the limited purpose of deciding voluntariness while keeping the results away from the members at trial.
Third, polygraph information can appear in investigative files, charging documents, or witness statements that the parties litigate before trial. Counsel routinely move to redact or exclude such references so the panel never learns that a test occurred. Because even a reference to taking or refusing a polygraph is barred, the cleanup is handled at the motions stage.
The line between admissibility and procedural use
The key distinction is between using polygraph results as substantive proof and confronting collateral procedural questions in which the existence of an examination is a background fact. MRE 707 bars the former absolutely. For the latter, a military judge sitting on a motion may need to understand that a polygraph happened in order to rule on a related issue, such as whether a post-test confession was voluntary, without ever admitting the results for their truth. The members who ultimately decide guilt are insulated from the polygraph entirely.
Practical implications for both sides
For the defense, the lesson is that a favorable polygraph cannot be presented to the members in an Article 120 case, so resources are better spent on admissible evidence and on litigating the voluntariness of any statement made in connection with a test. For the government, the same bar prevents reliance on an unfavorable result, and prosecutors must ensure that exhibits and witness testimony are scrubbed of polygraph references. For both, the pretrial stage is the time to obtain rulings that keep MRE 707 violations from ever reaching the panel.
Bottom line
Military courts exclude polygraph results categorically under MRE 707, a rule the Supreme Court upheld in United States v. Scheffer. In Article 120 pretrial motions, that exclusion means neither side can introduce examination results, opinions, or even references to taking or refusing a polygraph at trial. The only role polygraph information legitimately plays before trial is as background when a judge resolves a collateral question, such as the voluntariness of a confession obtained during the examination. Counsel use the motions stage to enforce the rule and to keep the panel from ever hearing about the test.
Disclaimer
This article is provided strictly for general educational and informational purposes. It is intended to explain how the Uniform Code of Military Justice (UCMJ), the Rules for Courts-Martial, the Military Rules of Evidence, and related military administrative processes work as a matter of public legal education. It does not constitute legal advice, a legal opinion, or a recommendation about any particular case, and it is not a substitute for advice from a qualified military defense attorney who can evaluate the specific facts and command, service, and jurisdictional circumstances involved.
Reading this article, or contacting any website on which it appears, does not create an attorney-client relationship between the reader and any law firm, attorney, or author. Every court-martial, nonjudicial punishment action, administrative separation, and security-clearance matter turns on its own facts, the charged articles, the convening authority, the service branch, and the evidence, and outcomes vary widely from one case to another.
Military law also changes over time. The Military Justice Act of 2016 (effective January 1, 2019) and subsequent National Defense Authorization Acts renumbered and rewrote many punitive articles, revised the Article 32 preliminary hearing, and altered sentencing, clemency, and appellate procedures. Statutes, regulations, executive orders, the Manual for Courts-Martial, and decisions of the service Courts of Criminal Appeals and the Court of Appeals for the Armed Forces may have been amended, superseded, or reinterpreted after this article was written, and article numbers or procedures cited here may have changed.
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