Maher v. People, 10 Mich. 212 (Mich. 1862)
Maher v. People is a cornerstone criminal law decision that crystallizes the doctrines of adequate provocation and heat of passion, and clarifies the jury's central role in assessing whether a killing (or an assault charged as an intent-to-murder offense) is mitigated from murder to manslaughter.
Whether, in a prosecution for assault with intent to murder, the trial court erred in excluding evidence that the defendant had learned of and had credible reason to believe in recent spousal adultery with the victim—evidence offered to show adequate provocation negating malice—and in effectively taking from the jury the question whether sufficient time had passed for the defendant's passion to cool.
In homicide and analogous offenses requiring malice (including assault with intent to murder), evidence of adequate provocation—such as the recent discovery of a spouse's adultery—may negate malice and mitigate the offense to manslaughter (or to a lesser assault). Adequate provocation is evaluated by an objective, reasonable-person standard, and whether a sufficient "cooling time" elapsed between the provocation and the act is ordinarily a question for the jury under all the circumstances. Evidence of what the defendant was told is admissible to show its effect on the defendant's state of mind, and circumstantial evidence of the provocative event is admissible to support the reasonableness and credibility of the asserted provocation.
Yes. The Michigan Supreme Court reversed the conviction and ordered a new trial. The excluded evidence of recent spousal adultery and the defendant's knowledge of it was admissible to show adequate provocation and to negate malice, and the question of whether there was sufficient cooling time was for the jury.
Maher v. People is a leading case on heat of passion and adequate provocation, repeatedly cited for three propositions: (1) discovery (or credible near-contemporaneous knowledge) of spousal adultery can constitute adequate provocation; (2) the question whether a reasonable cooling time elapsed is for the jury; and (3) evidence offered to show the defendant's state of mind and the reasonableness of his passion is admissible, even if some of it would be hearsay if offered for its truth. For law students, Maher connects the substance of manslaughter mitigation to evidentiary doctrines of relevance and state of mind, and it illustrates how these principles operate not only in completed homicides but also in intent-to-murder prosecutions.