Establishing Self-Defense Jury Instruction Standards for Deadly Force in Vehicle Assaults

Introduction

Bryant Ross Montoya v. State of Wyoming, 2025 WY 52 (May 8, 2025), is a Supreme Court of Wyoming decision that addresses the proper scope of self-defense jury instructions when a defendant uses a motor vehicle as a weapon. The appellant, Bryant Ross Montoya, appealed his conviction for felony property destruction after intentionally and repeatedly ramming his truck into another motorist’s vehicle during a highway confrontation. At the heart of the appeal was whether the district court erred by delivering self-defense instructions calibrated for “deadly force” rather than “non-deadly force,” given that a vehicle had been previously characterized as a deadly weapon. The Court’s unanimous opinion, authored by Chief Justice Fox, affirms the conviction, clarifies the plain-error standard in jury instructions, and reinforces how vehicles are treated in self-defense contexts.

Summary of the Judgment

A jury in Laramie County found Mr. Montoya guilty of felony property destruction after he backed his pickup into Samuel Kremer’s truck multiple times during a road-rage incident. Montoya claimed he acted in self-defense, fearing imminent serious bodily harm. At trial, the district court instructed the jury on self-defense using pattern instructions for deadly force, without objection from defense counsel. On appeal, Montoya argued that Wyoming law allows self-defense to prevent “any injury or loss,” not only “imminent death or serious bodily harm,” and that the court should have given non-deadly-force instructions. Applying the plain-error standard, the Supreme Court held that—although the terms “deadly force” and “imminent danger” were used—the overwhelming evidence showed Montoya was the aggressor. Therefore, he could not demonstrate the necessary “material prejudice” to his defense, and the judgment was affirmed.

Analysis

Precedents Cited

The Court’s discussion relies heavily on the standard for reviewing unpreserved instructional errors—plain error review—and on prior characterizations of a motor vehicle as a deadly weapon:

Iverson v. State, 2025 WY 19: Establishes the three-pronged plain-error test in Wyoming—(1) clear error in the record, (2) violation of a clear rule of law, and (3) material prejudice.
Kobielusz v. State, 2024 WY 10: Illustrates application of prong two (clear and unequivocal rule of law) in instructional error claims.
Lee v. State, 2024 WY 97: Defines “material prejudice” as a reasonable probability of a favorable verdict absent the error.
Green v. State, 2025 WY 20; Lynch v. State, 2024 WY 79: Reinforce that failure to meet any plain-error element precludes reversal.
Sindelar v. State, 2018 WY 29: Holds that erroneous self-defense instructions are harmless where the defendant’s theory is unsupported by evidence.
Prior consensus: Several Wyoming cases have recognized that motor vehicles may constitute deadly weapons in aggravated-assault contexts, justifying the use of deadly-force instructions when a defendant employs a vehicle as a weapon.

Legal Reasoning

The Supreme Court applied plain-error review because Montoya did not object at trial. The first prong was satisfied—the allegedly erroneous instructions appear in the record. Regarding the second prong, while the Court did not decide whether Wyoming law generally allows self-defense against mere “injury or loss” in property-destruction cases, it assumed arguendo that such defense existed. The opinion focuses on the third prong—material prejudice—and concludes that no reasonable probability exists that a jury would have reached a different verdict had non-deadly-force instructions been given. Key aspects:

Both Kremer and an independent witness, Sandberg, testified that Montoya was the aggressor and initiated force by ramming his truck.
No evidence suggested Kremer threatened Montoya with death or serious bodily injury at the moment of collision.
The State’s closing argument did not rely on the qualitative terms “deadly force” or “imminent danger,” but on Montoya’s role as aggressor.
Given the uncontested facts, the instructional nuance between non-deadly and deadly-force standards would not have altered the jury’s conclusion that Montoya lacked a lawful self-defense claim.

Impact

This decision reaffirms a strict application of the plain-error standard in Wyoming and underscores the following points for trial practitioners and courts:

Vehicles used to inflict harm are properly treated as deadly weapons in self-defense instructions, necessitating the “deadly force” pattern instructions.
Close attention to timely objection of jury instructions is critical; failure to object forfeits arguments on appeal except under narrow plain-error circumstances.
Proof of aggressive conduct that undermines a self-defense claim will usually outweigh technical instruction errors if no reasonable jury could find a lawful defensive justification.

Future cases involving road-rage or vehicular assaults must ensure that jury instructions align with the type of force alleged and that counsel preserves objections to any instructional mismatch.

Complex Concepts Simplified

Plain-Error Review: A legal standard allowing appellate courts to correct unobjected-to errors only if an error is obvious, breaks a clear rule, and likely affected the outcome.
Deadly vs. Non-Deadly Force: “Deadly force” means force likely to cause death or serious bodily injury; when a vehicle is used to ram another vehicle, it is treated as deadly force.
Material Prejudice: Demonstrating that, if not for the error, there is a reasonable chance the jury would have decided in the defendant’s favor.
Aggressor Doctrine: A person who starts or provokes violence cannot claim self-defense against the consequences of their own aggressive acts.

Conclusion

Montoya v. State of Wyoming confirms that, in vehicle-based assaults, self-defense instructions must be tailored to the deadly-force context. Even if a defendant argues for a broader self-defense right against property harm, a failure to object to pattern instructions—combined with incontrovertible evidence of aggression—precludes relief on appeal under Wyoming’s plain-error framework. The decision sharpens trial lawyers’ focus on early instruction conferences, preserves the integrity of jury guidance, and cements the principle that vehicles employed as weapons trigger the most stringent self-defense standards.