Concept
Modern Treatment of the Rule
Misdemeanor manslaughter
Modern Treatment of the Rule
The rule taught in the earlier sections, under which a death in the commission of an unlawful act short of a felony is involuntary manslaughter without proof of recklessness or negligence, describes the doctrine where it survives.1 It does not tell you whether a particular state still has it. California and roughly a dozen other states continue to accept the rule, while many jurisdictions have dropped it and limit involuntary manslaughter to conduct involving criminal negligence.2 The same killing can therefore be a homicide in one state and no homicide at all in the next. A student who applies the doctrine without checking whether the jurisdiction keeps it is analyzing under a rule that may not exist there. This section frames the two approaches, and the two subsections that follow work through how each one handles a case.
The states disagree because the rule trades one thing for another. Dispensing with proof of fault about the death makes a case simpler to prove, since the prosecution need only show that the unlawful act caused the death.3 It also attaches a serious penalty to breaking even a minor law, which gives people a reason to take small violations seriously. The price is that a defendant can be convicted of homicide without having been careless about anyone's life, so long as the violation happened to produce a death. Retaining states accept that price and keep the simplicity. Rejecting states conclude that liability for a death should depend on actual recklessness or criminal negligence about that death, and that a separate unlawful act should not stand in for it.
The statutes in retaining states show where the trade is written into the text. California's Penal Code §192(b) defines involuntary manslaughter as a killing "in the commission of an unlawful act, not amounting to a felony; or in the commission of a lawful act which might produce death, in an unlawful manner, or without due caution and circumspection."4 Oklahoma's statute is more explicit, making it manslaughter when a person, without a design to effect death, kills while engaged in the commission of a misdemeanor.5 When you read such a statute, ask what the predicate is (a misdemeanor, or the broader phrase "unlawful act"), whether the text contains any mental-state requirement about the death, and whether it has a second clause for lawful acts done carelessly. That second clause keeps a route open when the predicate fails. A driver who runs a red light and kills a pedestrian can be charged on either of two theories in a retaining state. The prosecution may argue that the conduct amounted to criminal negligence, or it may argue only that the unlawful act caused the death, in which case proof of criminal negligence becomes unnecessary.6 In a rejecting state only the first theory remains, so the same red-light facts are tested for criminal negligence and nothing else.
Retention does not mean the rule applies in its harshest form. In states that keep the doctrine, courts have moderated its worst effects with limits, and most of those limits resemble the ones that restrain the felony-murder rule.7 Those are the brakes covered earlier, including the malum in se and malum prohibitum distinction, foreseeability, dangerousness, and causation. On a bar problem, the facts will often tell you which approach the jurisdiction takes, and you should follow that instruction. Where the facts are silent, apply the common-law majority rules from the earlier sections. The first subsection below shows how a retaining jurisdiction writes and applies the rule, and the second shows how a rejecting jurisdiction analyzes the same facts.
Jurisdictions That Keep It
States that retain the unlawful-act doctrine write it into their homicide statutes in three recognizable ways, and the wording they choose decides which predicates qualify. Some keep the common-law formulation, which reaches a killing in the commission of an unlawful act not amounting to a felony, as California's involuntary manslaughter provision does.8 Others restate the idea in modern language, as Oklahoma does by making a killing manslaughter when a person engaged in a misdemeanor commits it without design to effect death.9 A third group lists the qualifying predicates and trims them, as Ohio and Kansas do.10 The retaining group includes states that never revised their criminal codes and about a dozen that kept the common-law rule when they did.11
The drafting choice matters because the phrase unlawful act is broader than the word misdemeanor. The common-law version apparently reached even conduct that was morally wrongful without being criminal, while a statute that says misdemeanor ties the predicate to a classification the legislature has already made.12 Under an Oklahoma-type text, a misdemeanor battery that ends in the victim's death falls within the statute on its terms, because the only questions are whether the defendant was engaged in a misdemeanor and killed without design to kill.13 The third form shows most clearly how legislatures narrow the rule while keeping it.
Ohio's involuntary manslaughter statute is the fullest example of that third form. One division covers a death caused as a proximate result of committing or attempting a felony, and a separate division covers a death caused as a proximate result of committing or attempting a misdemeanor of any degree, a regulatory offense, or a minor misdemeanor.14 The proximate-result language writes causation into the offense itself, so the prosecution cannot rest on a bare coincidence between the violation and the death. The statute also excludes minor misdemeanors under the motor vehicle code, together with municipal ordinances that are substantially equivalent to them.15 That carve-out answers a problem built into the rule. Minor traffic infractions are committed constantly by ordinary drivers, and if each could serve as the predicate, any fatal accident that happened to coincide with a trivial violation would carry a homicide conviction. Excluding the category by statute does at the outset what courts elsewhere do case by case through the distinction between inherently wrongful and merely regulatory offenses.
Kansas narrows the rule by a different route. Its involuntary manslaughter statute separately reaches reckless killings and a death caused by a lawful act done in an unlawful manner, and it admits a misdemeanor as a predicate only when the misdemeanor was enacted for the protection of human life or safety.16 The limit has a functional logic. A statute aimed at protecting life already targets the danger that a death realizes, so a death following its violation is the harm the legislature had in view, while a misdemeanor about record-keeping or fee payment says nothing about risk to life and falls outside. Ohio and Kansas therefore share a design: both keep the shortcut of dispensing with proof of fault about the death, and both confine it to predicates the legislature has judged serious enough to bear it.
Some legislatures apply the strict approach to one dangerous setting instead of to misdemeanors in general. Michigan, for example, has a statute under which a driver who exceeds the speed limit by even one mile per hour in a construction zone and thereby kills a worker may be held strictly liable for manslaughter and face up to fifteen years in prison.17 Strict liability here means liability without proof that the driver was careless about the death, so the violation and its fatal result are enough. The legislature has in effect decided in advance that speeding where workers stand beside moving traffic is dangerous enough to carry the weight of a homicide, and the prosecution need not prove negligence case by case. This is a state-specific variant and should not be generalized: in a state with no such provision, the same driver is tested under that state's ordinary rules for unlawful-act or negligent manslaughter.
Michigan's common-law background shows the ordinary doctrine that statutes like these build on. The Michigan Supreme Court treats involuntary manslaughter as the catch-all homicide, covering unintentional killings that are neither murder, voluntary manslaughter, nor justified or excused.18 Defining the offense through unlawful acts made sense because, at common law, a killing during an unlawful act intended to cause great bodily injury was murder, which left the unlawful acts without that intent to manslaughter.19 Once felony murder was widely accepted, the court restated the definition in People v. Ryczek as an unintentional killing, without malice, in doing an unlawful act that is not a felony and does not naturally tend to cause death or great bodily harm, or in negligently doing a lawful act or negligently omitting a legal duty.20 The decision that collects this history, People v. Holtschlag, is also cited for confining the doctrine to malum in se offenses, so Michigan illustrates both ends of retention: a common-law rule with a built-in limit alongside a statutory variant that dispenses with fault altogether.21
Recent decisions confirm that the rule is not a relic. In State v. Ervin, a New Jersey court upheld a homicide conviction of a defendant who had procured cocaine for himself and his girlfriend, and she died from it, reasoning that his distributing the cocaine to her caused her death.22 In State v. Weitbrecht, the Ohio Supreme Court upheld an involuntary manslaughter prosecution of a woman who crossed the centerline after a heart attack left her unconscious and killed three people, although she had not been negligent in doing so.23 Both results follow from the structure of the rule. When the prosecution must show only that an unlawful act caused the death, the defendant's lack of fault about the death is no defense, because the predicate stands in for the culpability that criminal negligence would otherwise have to supply. In a state that requires criminal negligence, the unconscious driver would present a far harder case for the prosecution, which is why the choice of jurisdiction can decide such facts, a point the next subsection develops.
These statutes teach one lesson about approaching a problem set in a retaining state. The usual mistake is assuming that every retaining state accepts every misdemeanor as a predicate, when Ohio excludes minor motor vehicle misdemeanors, Kansas admits only misdemeanors enacted to protect life or safety, and the construction-zone rule is a Michigan statutory variant rather than a general principle.24 Where the problem supplies statutory wording, that wording controls which unlawful acts qualify, and where the facts supply none, the common-law majority rules from the earlier sections fill the gap.
Jurisdictions That Reject It
A jurisdiction that rejects the unlawful-act doctrine refuses to let a violation of law stand in for fault about the death itself. The Model Penal Code abolishes the misdemeanor-manslaughter rule entirely, and a majority of states have done the same.26 Some states reach nearly the same result by a different route. They keep a manslaughter offense that mentions the misdemeanor, but they hold that the prosecution must prove criminal negligence in addition to it.27 Both routes end in the same place. The jury asks what the defendant knew or should have known about the risk of death, and it does not ask whether the defendant happened to be breaking some other law when the death occurred.
It helps to fix the retaining-state result on the same facts first, because here the outcome favoring the defendant belongs to the rejecting state and the conviction belongs to the retaining state. In State v. Hupf, a driver who failed to obey a stop sign and killed a pedestrian was convicted of involuntary manslaughter because the traffic-ordinance violation was the unlawful act. The decision has since been superseded by statute, so it shows the common-law rule and not current Delaware law.28 A Michigan driver who exceeds the limit by one mile per hour in a construction zone and kills a worker may likewise be held strictly liable for manslaughter and face up to fifteen years in prison, although that result rests on a Michigan statute and not on the general doctrine.29 In each example the violation carries the whole case, and the defendant's awareness of danger never becomes an issue.
A rejecting state changes what the prosecution must prove. Under the Model Penal Code, manslaughter is a reckless killing, meaning the defendant was aware of a substantial and unjustifiable risk of death and disregarded it. A killing that results from criminal negligence, which requires no awareness but does require a gross deviation from the care a reasonable person would take, is the lesser offense of negligent homicide.30 The unlawful act therefore has no independent role. It may still be admitted as a fact bearing on the defendant's state of mind, for instance where the rule broken exists to guard against the very danger that materialized, but the jury weighs it with everything else and may find it insufficient. The reason follows from what a violation actually shows. Offenses of this kind are committed every day by ordinary drivers who never perceive any risk to anyone, so a rule that treated each violation as the equivalent of fault about a death would convict people of homicide for bad luck. Rejecting states attach liability to the one thing that separates the careless from the unlucky, which is the defendant's own relationship to the risk of death.
Where a rejecting state does convict, the conviction rests on the mental state. In a common-law illustration, Stan, a lawyer who has worked thirty-six straight hours, knows he is exhausted and knows that driving while sleep deprived is dangerous, yet he drives home, drifts into the opposite lane, and kills Lisa.31 He is guilty of involuntary manslaughter because he knew of a substantial and unjustified risk of death and ran it, and that conclusion would follow whether or not drifting across the lane line was classified as a misdemeanor. A driver who dozed off with no prior warning stands differently. A person who never perceived the risk is not reckless, so the question under the Code becomes whether the failure to perceive it was a gross deviation from reasonable care.32
States that keep the misdemeanor language but add a negligence requirement reach the same destination by another mechanism. Under that approach, which a Montana decision, State v. Strobel, illustrates, the misdemeanor alone does not support the conviction, and the prosecution must also prove criminal negligence.33 Criminal negligence is a more demanding standard than the ordinary negligence of tort law, because virtually all courts require a higher degree of negligence for criminal liability, and for homicide in particular, than a civil plaintiff needs.34 Once that proof is required, the misdemeanor adds nothing independent: a defendant whose conduct was criminally negligent is liable without it, and a defendant whose conduct was not criminally negligent is not liable with it. The difference from the Code lies mainly in grading, since the Code separates reckless manslaughter from criminally negligent homicide. The contrast with retaining states shows most clearly in State v. Weitbrecht, where an Ohio court upheld an involuntary manslaughter prosecution of a driver who, rendered unconscious by a heart attack, crossed the centerline without negligence and killed three people.35 Under either rejecting approach the prosecution would have no recklessness or criminal negligence to point to, because the driver was not negligent at all.
Two errors recur in rejecting states. The first is treating rejection as an automatic acquittal, when a defendant who perceived the danger and ran it is liable whether or not the conduct also broke a traffic law. The second is equating criminal negligence with the ordinary carelessness that supports a civil suit, which understates what these states require.36