Service members under investigation for a sexual offense under Article 120 of the Uniform Code of Military Justice are sometimes asked whether they will take a polygraph, and many wonder whether passing one could clear them or whether failing one could be used against them. The answer requires separating two different things: how a polygraph might be used during an investigation, and whether the results can ever come into a court-martial. This article addresses both.
The Investigative Stage Versus the Courtroom
A polygraph is an investigative tool, not courtroom evidence. During an Article 120 investigation, military criminal investigators may offer a suspect the chance to take a polygraph examination. Investigators sometimes use the examination, and the interview that surrounds it, as a means of gathering information and assessing a suspect’s account.
The critical point is that whatever happens during a polygraph session is governed by the rules that protect a suspect. A polygraph examination of a service member who is a suspect is an interrogation, which means Article 31 rights and the right to counsel apply. Statements a suspect makes before, during, or after a polygraph, including any admissions made in the post-test interview, can themselves become evidence even though the polygraph chart cannot. This is one reason the decision to submit to an examination is significant and should not be made without legal advice.
Polygraph Results Are Not Admissible at Court-Martial
The central legal rule is Military Rule of Evidence 707. It provides that the results of a polygraph examination, the opinion of a polygraph examiner, and any reference to a person’s offer to take, failure to take, or taking of a polygraph examination are not admissible in a court-martial. The rule operates as a categorical bar rather than a case-by-case reliability assessment.
This means neither side can put polygraph results before the court. A passing result cannot be offered by the defense to show innocence, and a failing result cannot be offered by the government to show guilt. The mere fact that a person offered to take or refused a polygraph is also off limits.
The Supreme Court Upheld the Ban
The constitutionality of this exclusion was settled in United States v. Scheffer, 523 U.S. 303 (1998). In that case an Air Force airman who served as an informant took a polygraph that indicated no deception in his denial of drug use, but a urinalysis later showed methamphetamine. At his court-martial he sought to introduce the favorable polygraph result to support his defense, and Military Rule of Evidence 707 barred it.
The Supreme Court held that the per se exclusion of polygraph evidence under Military Rule of Evidence 707 does not unconstitutionally abridge an accused service member’s right to present a defense. The Court pointed to the continuing scientific controversy over the reliability of polygraphy and to the legitimate interest in avoiding collateral litigation over the validity of a given examination. After Scheffer, the categorical exclusion stands on firm constitutional footing, and the same logic that barred the favorable result in that case applies to an unfavorable result the government might wish to use.
Why the Military Draws a Firm Line
The categorical approach of Military Rule of Evidence 707 reflects a deliberate policy choice rather than an oversight. Courts and rule makers have long worried that a polygraph result invites the fact finder to surrender its own judgment about credibility to a machine and an examiner. In a sexual assault case under Article 120, where the verdict frequently turns on the relative believability of the accused and the complaining witness, that concern is acute. Allowing a polygraph result into evidence would risk turning the trial into a contest over the validity of the examination itself, complete with competing experts debating control questions, scoring methods, and the conditions of the test. The rule avoids that detour by keeping the result out entirely and leaving credibility where it belongs, with the members or the military judge.
It is also worth distinguishing the polygraph from other investigative techniques. Forensic evidence such as DNA, medical findings, and digital records can be admissible when properly authenticated and reliable. The polygraph stands apart precisely because the rule treats it as categorically inadmissible regardless of how it was conducted. A suspect should not assume that because some scientific evidence is admissible, polygraph results will be treated the same way.
What This Means for an Article 120 Case
Several practical implications follow for someone facing an Article 120 investigation.
First, a polygraph cannot be used to convict or to acquit inside the courtroom. A service member should not expect to clear an allegation by passing one, because the result will not be admitted, and the government cannot convict based on a failed examination either.
Second, the real risk of taking a polygraph lies not in the chart but in the statements made around it. Because the session is an interrogation, anything the suspect says can be used even though the polygraph result cannot. A suspect who agrees to a polygraph may end up making admissions in the accompanying interview that are admissible at trial.
Third, the decision whether to take a polygraph is a strategic one that should be made with counsel. The right to remain silent and the right to counsel apply, and a service member is generally not required to submit to an examination requested by investigators.
Conclusion
A polygraph can play a role at the investigative stage of an Article 120 case, but the results themselves cannot be used at court-martial. Military Rule of Evidence 707 categorically excludes polygraph results, examiner opinions, and references to taking or declining a polygraph, and the Supreme Court upheld that exclusion in United States v. Scheffer. The greater concern for a suspect is that statements made during the polygraph process remain fully usable. Anyone asked to take a polygraph during an Article 120 investigation should consult experienced military defense counsel before deciding. This article provides general legal information and is not legal advice for any specific matter.
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.
For these reasons, no reader should act or decline to act based on this content without first consulting a licensed attorney experienced in military justice about their own situation. The author and publisher make no warranty, express or implied, as to the accuracy, completeness, timeliness, or current applicability of the information provided, and disclaim any liability for any action taken or not taken in reliance on it. If you are facing investigation, charges, or an adverse administrative action, time limits may apply, and you should seek qualified counsel promptly.