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A Reasonable Standard for Self-Defense

In Canada this past week something happened that would not likely be very controversial in parts of the United States. A man named Jeremy David McDonald was at home in the morning when Michael Kyle Breen, who was already wanted for prior break-and-enter offenses, broke into McDonald’s house. McDonald defended himself with a knife, and Breen ended up with life-threatening injuries and had to be taken to hospital. In the U.S., we might be more surprised that Breen wasn’t shot, but McDonald would be protected in most states by stand-your-ground statutes. In Canada, however, McDonald was arrested and is facing charges of aggravated assault and assault with a weapon. The decision has prompted public outrage, fueled by increasing concerns about crime and the inability of the justice system to adequately respond. Legal experts, however, believe the public is getting things wrong. Is this simply a misunderstanding of the law or is there a larger issue here?

Before we proceed, there are two details worth noting. The first is that the public does not yet have all the details in this case. Second, one is legally entitled under Canadian law to defend themselves if they are attacked so long as the defense is “reasonable to the circumstances.” In other words, if someone pushes you, you can’t beat them with a tire iron and claim you acted in self-defense. Nevertheless, this is a case where McDonald’s house had been invaded by someone with a lengthy criminal record, and McDonald may have had reasonable concerns about his own safety and that of his family and his property. Ontario Premier Doug Ford, for example, claimed that the charges laid against McDonald demonstrate “something is broken in the system,” adding, “I know if someone breaks into my house or someone else’s, you’re going to fight for your life … This guy has a weapon … you’re going to use any force you can to protect your family.”

Much of the controversy stems from the difficulty in defining exactly what a “reasonable” response looks like in such situations. Self-defense laws are not usually that controversial in Canada, and few disagree with the abstract principle of self-defense being proportional to the threat. According to the police, it is unreasonable to continue to strike an attacker once they have been subdued. We don’t want people seeking vengeance or engaging in torture in the name of self-defense. Threat assessment is perhaps best left to professionals. Unfortunately, emergency services don’t always arrive when you need them. In 2024, a man in Ontario had an armed group break into his house and 911 put him on hold three times. In these minutes, anything could happen, and it might seem reasonable to arm oneself with a knife and to be prepared to use it in order to subdue an invader.

The ambiguities around mounting a “reasonable” defense can leave Canadians facing criminal charges. In 2010, Ian Thompson, a former firearms instructor, was charged with careless use of a firearm after firing warning shots into the air with a revolver in order to ward off arsonists attacking his home with Molotov cocktails. Some of the charges against Thompson were later dropped, and the then-Justice Minister expressed support for the idea of firing warning shots as a reasonable response. Meanwhile, the Liberal and NDP opposition, as well as as police associations, however, worried that this rhetoric would encourage vigilantism and produce more harm than good.

Ironically, over ten years later, the effect of this mindset may be the exact opposite. The risk-averse approach has produced a chilling effect on self-defense itself. The Canadian press is now reminding people that Canadians can, in fact, defend themselves if threatened, and warned of “misinformation” telling them otherwise.

Unfortunately, much of the legal establishment seems to be under the impression that it is the public’s responsibility to understand all of the nuances of what “reasonableness” entails. While laws do exist, much of the application is determined by a complex web of common law decisions. The result has been a standard that doesn’t seem so reasonable after all. This forces Canadians to measure their survival instincts against a post hoc legal fiction. Saying that it’s perfectly reasonable to cut someone who is attacking you in the heat of the moment, but that it is unreasonable to do so in an “aggravated” way is a rule that offers little practical guidance.

We may not know all the details in the McDonald case, but the conflicting responses from our political officials do suggest a larger problem. No one is advocating for mob justice, but the whole point of a “reasonable” standard is that it is action-guiding for average reasonable people. Laws in a democratic society are not static, but adapt to lived experience. They must be tested against the needs of real people if they are going to be a useful tool for coordinating social life. If there is widespread opposition to the way the law applies that standard, perhaps the problem is the isolation of law from the lived realities of average people, not people’s misunderstanding of legal nuance.

The Castle Doctrine and the Murder of Botham Jean

photograph of entrance to a castle

On October 1st, former police officer Amber Guyger was convicted of second-degree murder in the shooting of her neighbor, Dallas-area accountant Botham Jean. According to Guyger’s defense, she was returning home from work when she entered the wrong apartment; finding Jean inside and, believing him to be an intruder, shooting Jean in (claimed) self-defense. Nevertheless, the prosecution argued that Guyger’s actions were intentional, her contentious history with her victim was suspicious, that it was unlikely she could have been mistaken about her location, and that her training as a police officer should have better prepared her to think rationally under pressure. After only an hour of deliberation, jurors sentenced Guyger to ten years in prison.

A key component of Guyger’s defense was her stated belief that she was in her own home when she attacked Jean. Under Texas law, a defendant can be justified in using deadly force against an assailant if, among other conditions, the person “knew or had reason to believe that the person against whom the deadly force was used…unlawfully and with force entered, or was attempting to enter unlawfully and with force, the actor’s occupied habitation, vehicle, or place of business or employment.” Often dubbed the “Castle Doctrine” (after the adage that someone’s “home is their castle”), this concept is similar to so-called “Stand Your Ground” laws elsewhere in the country.

Passed in 2007, the Texas statute is designed to shield a defendant from legal penalties for killing a threat to their person. However, unlike many criminal proceedings, defendants making a self-defense claim must provide evidence that they were reasonably threatened and reacted rationally in the moment. Over the last decade, applications of the Castle Doctrine have ranged from homeowners fighting off armed robbers to the operator of a taco truck shooting and killing a man who had stolen and fled with a jar of about twenty dollars in tip money.

Asserting the Castle Doctrine is no guarantee that one’s defense will succeed – Raul Rodriguez, for example, was found guilty of murder after shooting his neighbor in 2010 during an argument over loud music – but several unusual cases, including Ezekiel Gilbert’s acquittal after killing a sex worker in 2009 and Joe Horn’s infamous 2007 murder of two men in his front yard just months after the rule’s passage (Horn was neither arrested nor indicted by a grand jury) exemplify the potentially problematic nature of the law. Since its creation, homicide rates have increased statewide with many of them evidencing racial bias against non-white defendants.

Philosophically, considerations of how one is allowed to protect themselves tend to emphasize two key factors for justifying an act of self-defense: proportionality and necessity. Proportionality captures the sense that self-defensive actions are only allowed to meet, but not exceed, the degree of threat posed to an agent: so, if someone is about to flick your nose with their fingers, it would violate proportionality if you shot them with a gun. Necessity, however, is simply whether any other option is available to the person considering lethal action; if you’re attacking me and I could either fight you or easily escape, necessity would require me to flee.

The interplay of these (and other) concepts results in several intuitively familiar principles: for example, if a person is able to run away from a threat, then they have a Duty to Retreat (because of necessity); or the Imminence restriction, which allows lethal force (because of proportionality, constrained by necessity) only in cases where threats are clearly about to result in harm.

The Castle Doctrine amounts to a denial of the necessity principle if certain other facts are true. Even if a defendant could feasibly escape from their attacker, defenders of the Castle Doctrine argue that, because of their property rights (for one example), they should not have to flee. Details beyond this vary from case to case; some argue that castle-defenders are also allowed to do whatever they want to a trespasser (on the notion that intruders forfeit all rights by breaking into a home), while others maintain that home-based self-defensive actions are still constrained by proportionality considerations.

Which returns us to the case of Amber Guyger, who (reportedly) thought she was in her own home, but was actually not. Many were surprised to learn that the presiding judge explicitly allowed jurors to consider the Castle Doctrine when deliberating over the case’s verdict; Guyger’s claim that she mistakenly entered the wrong apartment may have seemed unlikely enough to disqualify this as a potential legal shield. Nevertheless, a key element of the ethics of self-defense is often the perceived facts about the case, not necessarily the actual facts – given that self-defense often (though not necessarily always) happens in a momentary reaction without the opportunity for much reflection upon the available evidence. If Guyger somehow genuinely believed that she was in her own home, then there may indeed have been a legal case for applying the Castle Doctrine here.

However, the fact that there was considerable evidence to doubt the authenticity of Guyger’s belief regarding her location was clearly sufficient for the jury to rule against her claim of self-defense.

 

1 My thanks to Blake Hereth, Adam Blehm, and Stephen Irby for discussions regarding the ideas underlying this article.