Circumstantial Proof of “Physical Union” in Oral-Sex Rape and Plain-Error Review When No Acquittal Motions Are Made

1. Introduction

In Mayhan v. State (Del. Jan. 20, 2026), the Supreme Court of Delaware affirmed Byron Mayhan’s convictions arising from a series of sexual assaults against S.H. The appeal targeted only three convictions tied to events at an industrial park (“Location #2”): two counts of first-degree rape premised on forced oral sex and a related weapon offense.

The key appellate issue was evidentiary: Delaware’s rape statutes require proof of a “physical union” between the defendant’s genitalia and the victim’s mouth. Mayhan argued the State failed to present direct evidence of that “physical union” during its case-in-chief and, therefore, the trial court should have acquitted him sua sponte either at the close of the State’s case or after the verdict. He further argued the jury could not reasonably credit only the incriminating portion of his testimony (that oral sex occurred) while rejecting his claim of consent.

2. Summary of the Opinion

The Court affirmed. It held that (i) because Mayhan did not move for a directed verdict or for judgment of acquittal notwithstanding the verdict, review was for plain error; (ii) the jury could reasonably infer the required “physical union” from S.H.’s testimony that Mayhan “ejaculated in [her] mouth,” even without direct proof of genital-to-mouth contact; and (iii) the jury was entitled to accept parts of Mayhan’s testimony (that oral sex occurred) while rejecting other parts (that it was consensual).

3. Analysis

3.1. Precedents Cited

  • Swan v. State, 820 A.2d 342 (Del. 2003)
    Role in the decision: Establishes that when a defendant fails to move for a directed verdict or for judgment of acquittal notwithstanding the verdict, an insufficiency claim is reviewed only for plain error. The Court used Swan v. State to set the procedural posture and limit the scope of relief available to Mayhan.
  • Fisher v. State, 953 A.2d 258 (Del. 2008)
    Role in the decision: Defines plain error as an error “so clearly prejudicial to substantial rights as to jeopardize the fairness and integrity of the trial process.” By invoking Fisher v. State, the Court signaled that even if the evidence was debatable, reversal would require a particularly stark evidentiary failure—which it did not find here.
  • Monroe v. State, 652 A.2d 560 (Del. 19 95)
    Role in the decision: Provides the familiar sufficiency test: whether any rational trier of fact, viewing the evidence in the light most favorable to the State, could find guilt beyond a reasonable doubt. The Court also drew on Monroe v. State for the principle that it does not distinguish between direct and circumstantial evidence in this review posture.
  • Morales v. State, 696 A.2d 390 (Del. 1997)
    Role in the decision: Rejects the notion that the State must produce evidence consistent only with guilt; an alternative innocent explanation does not compel an insufficiency finding. This precedent directly undercut Mayhan’s theory that a “distance ejaculation” hypothesis negated the inference of “physical union.”
  • Washington v. State, 4 A.3d 375 (Del. 2010)
    Role in the decision: Reaffirms that credibility determinations and inferences from proven facts are for the fact finder. The Court used Washington v. State to explain why the trial judge had no obligation to override the jury’s weighing of testimony and permissible inferences.
  • Poon v. State, 880 A.2d 236 (Del. 2005)
    Role in the decision: States that the jury may accept part of a witness’s testimony and reject another part. The Court relied on Poon v. State (and the related quotation in Washington v. State) to reject Mayhan’s argument that the jury could not logically credit his admission of oral sex while rejecting his consent narrative.

3.2. Legal Reasoning

(a) Statutory elements and the “physical union” requirement. The Court grounded its analysis in the statutory framework for rape by oral sex. Under 11 Del. C. § 773(a) (first-degree rape) and the definition of “sexual intercourse” in 11 Del. C. § 761(h)(1), the State must prove an intentional, nonconsensual “physical union” of genitalia with the victim’s mouth. A “physical union” occurs upon “any penetration, however slight.” The opinion then asks whether the record permitted a rational inference of that union at Location #2.

(b) Sufficiency may rest on circumstantial evidence and reasonable inference. The defense sought to frame the case as lacking the “right kind” of proof—direct evidence of genital-to-mouth contact. The Court rejected that framing by applying Delaware’s sufficiency methodology: it does not privilege direct evidence over circumstantial evidence, and it asks only whether a rational factfinder could find the element beyond a reasonable doubt.

The Court treated S.H.’s testimony—Mayhan “ejaculated in [her] mouth”—as evidence from which a rational jury could infer genital-to-mouth “physical union.” Critically, the Court did not require the State to present an explicit description of penetration or contact; it held that the factfinder could infer the required element from the described act and surrounding context.

(c) Alternative innocent explanations do not compel acquittal. Mayhan argued there was another explanation consistent with innocence: ejaculation “from a distance,” without contact. Citing Morales v. State, the Court held that the possibility of an alternative explanation does not mandate a finding of insufficient evidence. Under the rational-jury standard, it was enough that the jury could reasonably infer “physical union,” even if a defense hypothesis could be imagined.

(d) No sua sponte acquittal obligation; plain-error posture matters. The Court emphasized that Mayhan did not move for a directed verdict at the close of the State’s case and did not move post-verdict for acquittal. Under Swan v. State and Fisher v. State, this raised the bar to reversal. The Court’s analysis thus implicitly reinforces a preservation rule: sufficiency challenges should be raised through timely motions if a defendant wants ordinary appellate review rather than the constrained plain-error lens.

(e) The jury may credit part of a defendant’s testimony. The defense claimed the jury could not rationally accept Mayhan’s admission that oral sex occurred while rejecting his broader claim that the encounter was consensual. The Court rejected that as contrary to basic factfinding principles, citing Washington v. State and Poon v. State: the jury may accept one portion of testimony and reject another, and credibility is within the jury’s sole province. On this view, the jury could find that oral sex happened (supported by Mayhan’s own testimony) and that it was nonconsensual (supported by S.H.’s account and the overall narrative of coercion).

3.3. Impact

1) Proof of “physical union” in oral-sex rape prosecutions. The decision underscores that Delaware juries may infer the “physical union” element from contextual testimony (here, ejaculation “in the mouth”) without requiring an express, anatomically detailed account of contact. Prosecutors may treat this as support for charging and proving oral-sex rape where the testimonial description implies contact and penetration, even if the witness does not explicitly describe penetration.

2) Reinforcement of preservation and the limits of sua sponte relief. The opinion signals that trial judges are not expected to intervene sua sponte to direct verdicts or enter post-verdict acquittals absent a defense motion, and that failure to preserve sufficiency arguments substantially constrains appellate relief under plain-error review.

3) Factfinder discretion on mixed credibility. By reaffirming that juries may accept portions of testimony and reject others, the decision limits a common appellate strategy in consent-based defenses—arguing that the jury’s selective acceptance of defendant admissions is “irrational.” The Court treats such selectivity as an ordinary feature of credibility assessment, not a logical flaw.

4. Complex Concepts Simplified

  • “Physical union”: In this context, it means genital-to-mouth penetration—“any penetration, however slight.” It does not require proof of injury or extended contact.
  • Direct vs. circumstantial evidence: Direct evidence proves a fact explicitly (e.g., a witness stating “his penis was in my mouth”). Circumstantial evidence supports an inference (e.g., “he ejaculated in my mouth,” from which a jury may infer contact/penetration). Delaware sufficiency review treats both the same.
  • Plain error: A heightened standard used when an issue was not properly raised at trial. The appellate court will reverse only for a clear, highly prejudicial error that undermines the fairness and integrity of the proceedings.
  • “Rational trier of fact” test: The appellate court does not decide what it believes happened; it asks whether a reasonable jury could have found guilt beyond a reasonable doubt, viewing evidence in the State’s favor.
  • Selectively crediting testimony: Juries can believe some statements from a witness (including a defendant) and disbelieve others. That is a standard feature of credibility determinations.

5. Conclusion

Mayhan v. State clarifies that Delaware’s “physical union” element for oral-sex rape may be proven through reasonable inference from testimonial facts such as ejaculation “in the mouth,” even without direct, explicit evidence of genital-to-mouth contact. The Court also reinforces two procedural and institutional principles: unpreserved sufficiency claims face strict plain-error review, and credibility—including the selective acceptance of parts of a defendant’s testimony—remains the jury’s domain. Together, these holdings make it harder to overturn oral-sex rape convictions on the theory that the State lacked “direct” proof of contact, especially where the defendant failed to timely seek acquittal at trial.