Service members sometimes try to bolster their credibility by pointing to a polygraph examination. In a typical scenario, the government has not arranged or requested any polygraph, so the accused obtains an examination privately, often through a civilian examiner, and then wants to introduce that examiner’s interpretation at trial to show truthfulness. The instinct is understandable. If an independent examiner concludes the accused showed no deception, why should the court-martial not hear it? The answer in the military justice system is clear and unfavorable to that instinct. A specific rule of evidence bars polygraph evidence in courts-martial, and it does so regardless of who conducted the examination or whether the government chose to pursue one.
Military Rule of Evidence 707 and its scope
The controlling authority is Military Rule of Evidence 707. The rule was enacted in 1991 and makes polygraph evidence categorically inadmissible in courts-martial. Its reach is deliberately broad. The rule bars three distinct categories of polygraph information from being admitted into evidence: the results of a polygraph examination, the opinion of the polygraph examiner, and any reference to an offer to take, a failure to take, or the taking of a polygraph examination.
Each of those categories matters to the third-party scenario. The “results” category bars the underlying charts and their scoring. The “opinion of the polygraph examiner” category is the one that directly forecloses a third-party interpretation, because an interpretation is exactly that, an examiner’s opinion about what the physiological data show. The third category sweeps in even the bare fact that an examination occurred, so an accused cannot circumvent the rule by alluding to a favorable test without offering the result itself. There is no exception in the rule for examinations arranged by the defense, conducted by a private or civilian examiner, or undertaken because the government declined to test. The identity of the examiner and the government’s posture toward testing are irrelevant to admissibility.
The government’s decision not to test changes nothing
A common misconception is that the government’s refusal to administer or request a polygraph somehow opens the door for the defense to offer its own. It does not. Military Rule of Evidence 707 is a flat prohibition that applies to the evidence itself, not to a particular party. Because the rule excludes the examiner’s opinion and any reference to the examination, a privately obtained, third-party interpretation falls squarely within the prohibition. The …