The Jury Is the Lie Detector: Wyoming Supreme Court Rejects Polygraph-Based Ineffective Assistance Claim Under Rule 702 and Daubert

Introduction

In Randall Bruce Morris v. The State of Wyoming (2025 WY 98), the Wyoming Supreme Court affirmed the denial of a motion for a new trial premised on ineffective assistance of counsel. The motion centered on trial counsel’s failure to request a Daubert hearing to admit the defendant’s “no deception indicated” polygraph results. The Court held that even if a Daubert hearing had been sought, the polygraph results would have been inadmissible under Wyoming Rule of Evidence (W.R.E.) 702 because they neither aided the jury nor satisfied Daubert’s reliability and “fit” requirements. The Court further declined to presume prejudice, distinguishing the narrow circumstances of King v. State.

The case involved grave allegations: Morris was convicted of two counts of first-degree sexual abuse of a minor and one count of second-degree sexual abuse stemming from incidents in May and late August 2022 involving his ten-year-old step-granddaughter, BA. The State’s trial motion excluded polygraph evidence; the jury convicted on all counts. While the direct appeal was stayed, Morris pursued a motion for new trial under W.R.A.P. 21 based on ineffective assistance; the district court denied relief, and the Supreme Court now affirms.

Summary of the Judgment

The Supreme Court affirmed the district court’s denial of Morris’s W.R.A.P. 21 motion. Applying Strickland’s two-pronged framework, the Court resolved the ineffective assistance claim on the prejudice prong and concluded:

Even if counsel had requested a Daubert hearing, the polygraph results would have been inadmissible under W.R.E. 702.
The proposed use—bolstering Morris’s credibility—would impermissibly invade the jury’s role as the exclusive arbiter of credibility.
The record at the Rule 21 hearing failed to establish Daubert reliability: there was insufficient evidence of peer review details, error rates, standards, or general acceptance of current techniques.
The polygraph did not “fit” the facts: the question asked about “that Sunday in August,” while the abuse occurred in May and on a Saturday in August.
No presumption of prejudice applied; King’s narrow presumption was distinguishable and has since been criticized.

As a result, Morris could not demonstrate a reasonable probability that admission of the polygraph would have changed the outcome of trial, and the Court affirmed.

Key Facts and Procedural Background

Allegations: In May 2022, Morris allegedly showed pornographic videos to BA, touched and kissed her breasts, and digitally penetrated her anus. In late August 2022, during a weekend when BA’s parents were out of town for a Broncos preseason game, Morris allegedly digitally penetrated BA’s vagina on a Saturday night.
Investigation: After the disclosure in October 2022, a forensic interview captured BA’s account. Morris denied wrongdoing but agreed to a polygraph. The relevant polygraph question—crafted by the examiner in consultation with Morris—asked whether Morris had touched the child’s vagina or buttocks “skin to skin” on “that Sunday in August” when the Vikings played the Broncos. The score was “no deception indicated.”
Trial: The State moved to exclude any polygraph evidence under W.R.E. 702 and 403; the court granted the motion. The jury convicted Morris on all counts and the court imposed consecutive sentences.
Rule 21 Motion: While direct appeal was stayed, Morris sought a new trial for ineffective assistance, arguing counsel should have demanded a Daubert hearing to admit the polygraph. The district court denied relief on prejudice grounds, finding the polygraph inadmissible under Rule 702.
Appeal: The Supreme Court consolidated the direct appeal and the Rule 21 appeal; only the denial of the Rule 21 motion was at issue on appeal.

Detailed Analysis

Precedents Cited and Their Influence

Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579: Establishes the federal standard for expert evidence reliability and relevance. Wyoming expressly adopted Daubert’s analytical framework in Bunting v. Jamieson, guiding Rule 702 admissibility assessments.
Bunting v. Jamieson, 984 P.2d 467 (Wyo. 1999): Wyoming’s adoption of Daubert and its two-part inquiry—reliability and “fit.”
Reichert v. Phipps, Cramer v. Powder River Coal, LLC, Hardman v. State, Loepp v. Ford: Wyoming cases elaborating on Daubert’s factors—testability, peer review and publication, error rates and standards, acceptance in the scientific community, expert experience, independence of research, and nonjudicial uses—and clarifying the “fit” requirement’s focus on helpfulness and connection to disputed facts.
Strickland v. Washington: The source of the two-pronged ineffective assistance test—deficient performance and prejudice. The Court consistently applies and often resolves IAC claims on the prejudice prong where dispositive. Wyoming cases following this approach include Winters, Mellott, Jendresen, Leners, Fairbourn, McNaughton, and Sen.
Nania v. State (2025 WY 16) and Craft v. State: Reaffirm the rule that the “jury is the lie detector” and that expert testimony cannot vouch for credibility or truthfulness of witnesses, including alleged victims and defendants. W.R.E. 704 allows opinions embracing ultimate issues, but not credibility opinions.
King v. State, with critiques in Pickering v. State and Winters: King had presumed prejudice where counsel failed to investigate and secure critical eyewitnesses. The present case distinguishes King because the polygraph evidence was neither exculpatory nor admissible. Wyoming has narrowed King’s force, confining presumed prejudice to rare circumstances not present here.
Jackson v. State and Castellanos v. State: Mere speculation cannot establish prejudice; concrete evidentiary showings are required. Applied here to reject speculative claims that a Daubert hearing would have resulted in admissible polygraph evidence changing the trial outcome.

Legal Reasoning Applied by the Court

Strickland Prejudice as the Dispositive Prong. The Court chose the prejudice prong first—an accepted practice when it is dispositive. The defendant had to show a reasonable probability that, but for counsel’s omission (failing to request a Daubert hearing), the outcome would have been different. That required proof that the polygraph would (a) have been admissible and (b) materially affected the verdict.
Rule 702 Helpfulness: Polygraph as Credibility Bolstering Is Not Admissible. Defense counsel’s stated purpose was to use the polygraph results to bolster Morris’s credibility. Wyoming’s evidence law forbids expert testimony that evaluates or vouches for witness credibility. Because “the jury is the lie detector,” any expert testimony that tends to substitute an expert’s view for the jury’s credibility determination fails Rule 702’s helpfulness requirement. Thus, the polygraph results, offered to prove Morris was truthful, would not assist the trier of fact and would invade the jury’s exclusive province.
Daubert Reliability Not Established on the Record. The record at the Rule 21 hearing—featuring only the test administrator—did not carry the proponent’s burden under Daubert’s reliability factors:
- While the examiner referenced training and general scientific testing, he could not explain the peer review process or identify the peer reviewers, undermining peer review/showing of scientific foundations.
- He did not provide evidence of known or potential error rates for current polygraph methods, or the existence and maintenance of standards controlling the technique’s operation.
- He lacked publications and had not been certified as an expert to testify in criminal trials on polygraph methodology; his primary practice was law-enforcement hiring, a nonjudicial use with different stakes.
On this record, the Court found reliability unproven under Daubert.
“Fit” Failure: The Question Did Not Address the Charged Acts. The polygraph question was circumscribed to “that Sunday in August” identified with a specific football game weekend. But the charged conduct occurred in May 2022 and on a Saturday in late August. The examiner himself emphasized that polygraph validity is dependent on specific questions and times. Thus, the “no deception indicated” result did not fit the facts actually in dispute and would not help the jury decide whether the charged acts occurred.
No Reasonable Probability of a Different Result. Because the polygraph results were inadmissible for multiple independent reasons, Morris could not show a reasonable probability of a different trial outcome. The claimed impeachment value—challenging the detective’s continued investigation after a “pass”—was likewise inadmissible and unpersuasive given the mismatch in dates and the non-utility of credibility bolstering evidence.
No Presumption of Prejudice. The Court declined to presume prejudice (as in King), noting both that King has been criticized and that the conditions for presumption were absent. Unlike King’s unpresented eyewitness testimony likely corroborating innocence, the polygraph here was neither exculpatory nor admissible.

Impact and Significance

Firm Reaffirmation: Polygraphs Are Not a Path to Credibility Proof. Morris cements the principle that polygraph evidence offered to show a defendant’s truthfulness will almost invariably be excluded under Rule 702, both for lack of helpfulness and for invading the jury’s credibility function. Practitioners should not expect polygraphs to be admitted for “truthfulness” proof or backdoor credibility vouching.
Daubert Burden Clarified for Post-Trial Ineffective Assistance Claims. When alleging ineffective assistance for failure to seek a Daubert hearing, defendants must present a robust evidentiary foundation at the Rule 21 hearing to show the proffered evidence would satisfy Daubert’s reliability and fit. Speculation or sparse examiner testimony will not suffice. The decision underscores that admissibility is a predicate to proving Strickland prejudice.
“Fit” Matters as Much as Reliability. Even if a technique can be defended as generally reliable, a proffer fails if the question or method does not track the actual disputes at trial. Here, the precise timeframe limitation (Sunday vs. Saturday/May) was fatal. This is a reminder to litigants that Daubert’s “fit” is a stringent relevance test, not a formality.
Presumption of Prejudice Narrowed. Morris continues Wyoming’s trajectory of cabining King. Presumption remains “rare” and is inapplicable where the omitted evidence is inadmissible, tangential, or non-exculpatory. Counsel’s failure to pursue a potentially excludable line of proof will not trigger presumption.
Law Enforcement and Investigative Practice. While polygraphs may retain administrative or investigative utility, Morris makes clear that a “no deception indicated” result cannot be repurposed to impeach the propriety of continued investigation or to influence jurors regarding credibility. Trial courts will exclude such efforts.

Complex Concepts Simplified

Ineffective Assistance of Counsel (Strickland). To win, a defendant must prove two things: (1) counsel performed deficiently compared to a reasonably competent attorney; and (2) prejudice—a reasonable probability of a different outcome but for the deficiency. Courts often decide these claims on prejudice alone if easier or dispositive.
W.R.A.P. 21 Motion for New Trial. A post-trial mechanism used in Wyoming to assert claims like ineffective assistance. The defendant must develop an evidentiary record at the hearing; mere arguments are insufficient.
Rule 702 and Daubert. Expert testimony is admissible only if it is helpful to the jury, based on sufficient facts or data, derived from reliable principles and methods, and reliably applied. Daubert adds a non-exclusive reliability checklist (testability, peer review, error rates, standards, acceptance, etc.) and a “fit” requirement—does the expert’s opinion connect to the actual disputed facts?
“The Jury Is the Lie Detector.” Courts bar expert testimony that tells jurors who is truthful or who to believe. Credibility assessments are for the jury alone. Polygraphs offered to show a witness is telling the truth fall afoul of this principle.
Vouching vs. Ultimate Issue Opinion. While Rule 704 permits opinions embracing the ultimate issue (e.g., cause of injury), neither experts nor lay witnesses may opine that another witness is truthful or that the accused is guilty—this is vouching and is prohibited.
Why “Fit” Sank the Polygraph Here. The polygraph tested a different time (“that Sunday”) than the time charged (May and a Saturday). A test that doesn’t address the disputed events can’t help the jury decide the case and fails Daubert’s relevance/fit prong.

Practice Pointers

If considering polygraph evidence, anticipate Rule 702 objections: you will need a qualified expert capable of addressing Daubert factors with specifics—peer review citations, contemporary error rates, operating standards, and acceptance within the relevant scientific community.
Avoid offering polygraphs to prove a party’s truthfulness; courts will treat this as impermissible vouching that invades the jury’s function.
Ensure “fit”: tailor any expert methodology and questioning to the precise facts and dates truly in dispute.
For Rule 21 IAC claims grounded in evidentiary omissions, bring the evidence to the hearing. Without a robust, admissible foundation, prejudice cannot be shown.
Do not rely on King’s presumption of prejudice. Wyoming treats presumed prejudice as rare, and it does not extend to failures to pursue evidence that is inadmissible or not outcome-determinative.

Conclusion

Morris v. State crystallizes three durable propositions in Wyoming law. First, polygraph evidence aimed at bolstering credibility fails Rule 702’s helpfulness requirement and violates the bedrock rule that “the jury is the lie detector.” Second, under Strickland’s prejudice prong, a defendant alleging counsel erred by not seeking a Daubert hearing must show the proffered evidence would be admissible and likely outcome-changing; mere conjecture is insufficient. Third, the presumption of prejudice is rare and does not apply where the omitted evidence lacks admissibility and exculpatory force.

In the broader legal landscape, this decision reinforces the centrality of Daubert’s reliability-and-fit framework, underscores the jury’s exclusive role in assessing credibility, and sets a pragmatic evidentiary bar for post-trial ineffective assistance claims. Practitioners should treat Morris as a cautionary guide: without a rigorous scientific foundation and a tight nexus to the facts in dispute, expert evidence—especially polygraph results—will not clear Wyoming’s Rule 702 gate.