Concurring Supreme Court of Wyoming Justice Argues Against Blanket Ban on Admission of Polygraph Results

In every state except for New Mexico, polygraph results are generally inadmissible absent a stipulation by the parties that they should be admitted. But, according to a concurring justice of the Supreme Court of Wyoming, there is a decades-old opinion in the Cowboy State that provides for something other than a blanket ban on their admission.

In Nania v. State, 2025 WL 379835 (Wyo. 2025), a majority of the Supreme Court of Wyoming found no problem with the trial judge per se precluding the defendant from introducing polygraph results in the absence of a stipulation between the parties. But Justice Boomgaarden wrote a special concurrence joined by Chief Justice, which stated the following:

Our precedent from Cullin v. State, 565 P.2d 445, 455 (Wyo. 1977), was the first Wyoming case to meaningfully discuss the admissibility of polygraph results, but it did not adopt a bright line rule. It adopted a rule that hinged on reliability, based on a Tenth Circuit decision:

However, we do not base admissibility of polygraph results solely upon the basis of the stipulation. There should be some test of reasonable reliability before final admission by the judge, even though the parties agree. We see no real or unusual problem in that regard and believe that it can be accomplished through existing, accepted rules of evidence.

The Tenth Circuit approached the problem in a practical way. In that case, the defendant offered evidence of a polygraph examination and to submit himself to a government polygraph test. The court declared that in a proper case a polygraph test may be admissible but a foundation must be laid by relevant expert testimony relating to the probative value of such evidence and that before admission, the test is an accepted one in his profession and has a reasonable measure of precision in its indications. Id. at 457 (emphasis added) (citations omitted).

Our subsequent cases did not adopt a per se rule excluding polygraph evidence. Schmunk addressed references made to polygraph testing, including a refusal to take a polygraph, and whether those references were reversible error. Schmunk v. State, 714 P.2d 724 (Wyo. 1986). We addressed the same issue in Proffit v. State, 193 P.3d 228, 233 (Wyo. 2008), when we described references to a refusal to take a polygraph test to be overzealous prosecution. In neither instance did we address the advancements of polygraph technology, the advancements in the law of evidence after Daubert, or the admissibility of polygraph evidence proffered by either party.

Our decision in Cullin set the stage for polygraph evidence to be tested under the yet-to-be-established parameters of Daubert, just as the trial courts and parties test the reliability and relevance of other scientific expert testimony. We saw “no reason why the polygraph expert should be treated in any more restrictive manner than other experts.”...We went on to prescribe that the trial courts must find a modicum of reliability for the polygraph evidence to have probative value, and that cross-examination and impeachment are the methods to “smoke[ ] out the inept, the unlearned, the inadequate self-styled expert.”...We also recognized W.R.E. 403 as an umbrella of protection to exclude relevant evidence if its probative value is outweighed by prejudice, confusion or the risk of misleading....We limited our analysis in Cullin to a polygraph the parties stipulated for admission, but our discussion did not close the door to unstipulated polygraph evidence. Rather, we expressly kept that door open “for another day when the question is directly before us.”...The question is now directly before us....

I do not urge the adoption of a blanket rule of admissibility of polygraph evidence. I urge only that Wyoming courts decline a per se rule of inadmissibility, instead adhering to our mandate in Cullin to consider such evidence for reliability and relevance, subject to exclusion through W.R.E. 403. With our post-Cullin adoption of the Daubert structure to test such evidence through W.R.E. 702, we have ample precedent in place and reliability factors for the trial courts to use.

-CM