“Substance” Means the Entire Product: Colorado Narrows Involuntary Intoxication When Multiple Intoxicants Are Alleged

Case: The People of the State of Colorado v. Isaac U. Mion
Citation: People v. Mion, 2026 CO 5, 24SC2 (Colo. Jan 26, 2026)
Court: Colorado Supreme Court (Boatright, J., majority; Marquez, C.J., dissenting; Hood, J., dissenting)
Disposition: Court of appeals reversed; case remanded

I. Introduction

People v. Mion addresses the scope of Colorado’s statutory affirmative defense of involuntary intoxication under section 18-1-804, C.R.S. (2025), in a recurring modern scenario: a defendant claims to have consumed an intoxicating product (here, a joint) that allegedly contained an additional unknown intoxicant, and that the unknown intoxicant—rather than the expected one—produced a mental state that negated criminal responsibility.

Isaac U. Mion was charged with aggravated robbery, menacing, and criminal mischief following erratic behavior after he smoked a joint obtained from a person he did not know by name. At trial, Mion testified that the joint contained “something unknown” and sought a jury instruction on involuntary intoxication. The trial court refused the instruction as speculative, but a division of the court of appeals reversed, creating a three-part rule for “multiple intoxicants.” The Colorado Supreme Court granted certiorari to consider whether that appellate rule improperly removed considerations of blameworthiness embedded in the statute’s “ought to know” language and thereby expanded the defense beyond the legislature’s design.

II. Summary of the Opinion

III. Analysis

A. Precedents Cited

1. Statutory interpretation framework

• People v. Garcia, 113 P.3d 775 (Colo. 2005): Cited for de novo review of statutory interpretation and for the principle that courts review the record as a whole to determine whether there is “any evidence tending to establish” a defense (quoting Idrogo v. People). The majority uses Garcia both procedurally (standard of review) and substantively (defense-instruction threshold).
• People v. Cali, 2020 CO 20, 459 P.3d 516: Reinforces the “plain meaning” starting point.
• McCoy v. People, 2019 CO 44, 442 P.3d 379: Supplies the court’s ambiguity standard (“reasonably susceptible of multiple interpretations”) and authorizes resort to consequences and other interpretive tools once ambiguity is found.

2. Mens rea vocabulary and “ought to know” as reasonableness

• People v. Krovarz, 697 P.2d 378 (Colo. 1985), and People v. Etchells, 646 P.2d 950 (Colo. 1982): Used to confirm that “knowingly” requires actual awareness, not what a person “should have been aware” of. This supports the majority’s view that section 18-1-804(5) deliberately combines two distinct fault concepts: actual awareness (“knowingly introduced”) plus negligence-like reasonableness (“ought to know”).
• People v. Turner, 680 P.2d 1290 (Colo.App. 1983): Central to two points. First, it articulates that “ought to know” is evaluated with common knowledge and circumstances; second, it provides the “something more than an unsupported assertion” requirement for the “some credible evidence” threshold.
• Gatewood v. State, 654 S.W.3d 239 (Tex. Ct. App. 2022): Cited as persuasive authority that voluntary intoxication can rest on “should have known through the exercise of reasonable care” reasoning, reinforcing the majority’s understanding of “ought to know.”

3. Guardrails against expansive intoxication defenses

• People v. Williams, 2025 COA 26, 568 P.3d 1267: The majority uses Williams to illustrate an undesirable consequence of the court of appeals division’s “multiple intoxicants” approach: a defendant claiming he intended one illegal drug but ingested another could attempt to recast the episode as “involuntary.” Even though Williams rejected the defense on causation evidence, the majority treats the scenario as evidence that the legislature likely did not intend broad protection for highly culpable defendants.
• Harvey v. Cath. Health Initiatives, 2021 CO 65, 495 P.3d 935: Cited for the canon against surplusage; the majority deploys it to justify giving operative meaning to section 18-1-804(5)’s exception language (“under circumstances that would afford a defense to a charge of crime”).

4. Common-law and model-code context

• City of Minneapolis v. Altimus, 238 N.W.2d 851 (Minn. 1976): Referenced to note that “innocent mistake” is a common-law concept, but the majority declines to import that requirement into Colorado’s codified defense.
• Model Penal Code and Commentaries § 2.08 (1962) and Model Penal Code § 2.08 cmt. 6 (A.L.I., Tentative Draft No. 9 1959): The majority uses the MPC lineage to support the notion that intoxication caused by another’s fraud is “not self-induced,” bolstering its reading that a “spiked drink” situation can still fit the statutory exception even if the “product” framing controls.

5. Instructional-error doctrine in the dissents

• Pearson v. People, 2022 CO 4, 502 P.3d 1003: In the Marquez dissent, cited for the proposition that failure to instruct on an affirmative defense when supported by “some credible evidence” implicates constitutional rights and triggers constitutional harmless-error review.
• Galvan v. People, 2020 CO 82, 476 P.3d 746: In the Hood dissent, cited for the “small quantum” of evidence necessary to warrant an instruction.

B. Legal Reasoning

1. The statutory structure: two prongs of “self-induced intoxication”

The majority’s interpretive move begins with section 18-1-804(5)’s definition of “[s]elf-induced intoxication,” which it reads as containing two independent culpability gates:

• Prong 1 (actual awareness): the defendant “knowingly introduced” the substance.
• Prong 2 (reasonableness): the defendant “knows or ought to know” the substance tends to cause intoxication.

This matters because the court views the court of appeals’ “particular intoxicant” focus as functionally collapsing the statute into Prong 1 alone— allowing defendants to avoid the “ought to know” inquiry simply by alleging an unknown adulterant.

2. Ambiguity and the key choice: what is the “substance”?

Because “substance” is undefined and plausibly refers either to (a) the entire consumable product (a joint, a brownie, a drink) or (b) a constituent intoxicant (THC, stimulant, hallucinogen), the majority finds ambiguity and turns to consequential reasoning under section 2-4-203(1), C.R.S. (2025).

3. Consequences: preserving “ought to know” and factfinder evaluation of circumstances

The court rejects the division’s segmentation approach (“particular intoxicant”) because it would often prevent courts and juries from evaluating whether the defendant acted unreasonably in consuming an obviously intoxicating product under risky conditions. The majority’s pot-brownie hypothetical illustrates the point: if the “substance” is THC rather than the brownie, a defendant could claim ignorance of THC and thereby bypass whether a reasonable person should have known the brownie was intoxicating.

By defining the “substance” as the entire product, the “knowingly introduced” prong is usually satisfied (people knowingly eat brownies and smoke joints), and litigation shifts to what the defendant knew or should have known given the surrounding circumstances—precisely the inquiry the legislature embedded in the “ought to know” clause.

4. Application to Mion

Under the “product” definition, the court holds Mion failed to present “some credible evidence” that his intoxication was not self-induced because: (1) he knowingly smoked the joint (“two hits”), and (2) he knew or should have known it would intoxicate, given that it was a street drug obtained from someone he did not know by name and smoked without asking what it was.

5. The spiked-drink objection and the statutory exception

Addressing the concern that the “product” rule would bar truly blameless defendants (e.g., drinks secretly spiked), the majority points to the statutory carve-out within section 18-1-804(5): intoxication is not self-induced if the substance was introduced “pursuant to medical advice or under circumstances that would afford a defense to a charge of crime.” The majority, bolstered by MPC commentary about fraud, suggests that covert spiking involves fraud/trickery and may fit this exception, whereas Mion’s scenario did not involve evidence of trickery—only acceptance of an unspecified joint.

6. The dissents’ core statutory critique

Chief Justice Marquez and Justice Hood disagree with the majority’s unit-of-analysis. They read “substance” as the intoxicant that caused the disturbance described in section 18-1-804(4) and argue that the majority’s product-based framing wrongly forecloses jury consideration where someone knowingly consumes a mild legal intoxicant but unknowingly consumes a second intoxicant that drives the loss of control.

They also dispute the majority’s reliance on the exception clause to save spiked-drink cases, questioning what independent “defense to a charge of crime” would fit and whether the majority’s approach can coherently distinguish victims of spiking from defendants like Mion based solely on venue or sourcing.

C. Impact

1. The new rule

The decision establishes a controlling interpretive rule for section 18-1-804(5): in “multiple intoxicant” claims, the “substance” is the entire product consumed, not the particular intoxicant within it.

2. Likely effects on defense strategy and trial-court gatekeeping

• Fewer instructions in adulterant cases: Defendants alleging unknown additives in drugs or consumables will more often be deemed voluntarily intoxicated, because knowingly ingesting the product is straightforward and “ought to know” can be satisfied by risky sourcing circumstances.
• Greater emphasis on “ought to know” facts: Litigation will pivot to reasonableness—how the product was obtained, whether it was labeled, whether it came from a licensed establishment, whether the defendant asked what it was, and the general foreseeability of intoxication.
• Exception clause litigation: The phrase “under circumstances that would afford a defense to a charge of crime” is positioned to become the next battleground, especially for spiking, fraud, coercion, or sabotage scenarios. The majority acknowledges ambiguity but treats the clause as meaningful.

3. Relationship to the court of appeals’ experiment

The ruling expressly disapproves the court of appeals division’s three-part “multiple intoxicants” test from People v. Mion, 2023 COA 110M, 544 P.3d 111, and thereby removes a doctrinal opening for involuntary intoxication claims premised on “I meant to ingest X but got Y.”

IV. Complex Concepts Simplified

• Affirmative defense: A defense the defendant may raise that, if supported by evidence, requires the prosecution to disprove it beyond a reasonable doubt (Colorado procedure is reflected in section 18-1-407(1), C.R.S. (2025)).
• Involuntary intoxication (section 18-1-804(3)): A defendant is not criminally responsible if intoxication that is not self-induced causes a lack of capacity to conform conduct to the law.
• Self-induced intoxication (section 18-1-804(5)): Intoxication is “self-induced” when the defendant knowingly introduced the substance and knew or should have known it tends to intoxicate (with certain exceptions, e.g., medical advice or other exculpatory circumstances).
• “Knowingly” vs. “ought to know”: “Knowingly” is actual awareness; “ought to know” asks what a reasonable person would have understood in the circumstances. The majority treats both as deliberate legislative choices about blameworthiness.
• “Some credible evidence” threshold: To get a jury instruction on an affirmative defense, a defendant must offer more than speculation—“something more than an unsupported assertion” (drawing from People v. Turner).
• Statutory ambiguity: A term is ambiguous if it reasonably supports more than one meaning. Once ambiguous, courts may consider consequences and purpose to select the interpretation that best reflects legislative intent (as framed by McCoy v. People).

V. Conclusion

People v. Mion is a consequential narrowing of Colorado’s involuntary intoxication defense in adulterant or “multiple intoxicant” scenarios. The Supreme Court’s core holding—treating the “substance” in section 18-1-804(5) as the entire product consumed—preserves the statute’s “ought to know” reasonableness inquiry and limits defendants’ ability to recharacterize risky consumption decisions as legally involuntary intoxication.

The dissents warn that the product-based framing risks criminal liability for otherwise blameless defendants who unknowingly ingest a second intoxicant and question whether the statutory exception can adequately protect spiking victims. Future cases will likely test the boundaries of that exception clause and clarify what “circumstances that would afford a defense to a charge of crime” means in intoxication-by-fraud and sabotage contexts.