The Michigan Supreme Court will hear argument on October 9 to revisit whether the 2001 Carpenter court correctly determined that the Michigan Legislature abolished the diminished capacity (failure of proof) defense for specific-intent crimes when MCL 768.21a was adopted in 1975. People v Carpenter, 464 Mich 223, 241 (2001).

Two defense options before Carpenter

For over 25 years before Carpenter, a Michigan defendant had two options when claiming a mental illness or intellectual disability as a defense against a crime:

[1] An affirmative insanity defense. Insanity does not involve an offense element. The crime is admitted, but the insanity defense tries to excuse or justify its commission.

[2] For specific-intent crimes, the failure of proof of specific intent because of diminished capacity. Unlike insanity, diminished-capacity evidence is not an affirmative defense. Diminished-capacity evidence is a way for the defendant to offer evidence of some mental abnormality to disprove any required specific-intent element of an offense.

See also House Legislative Analysis, SB 202 (Substitute H-1) (March 3, 1994), p 2.

The Carpenter court abolished the diminished-capacity defense

In contrast to California’s 1981 Legislature—which expressly codified “The defense of diminished capacity is hereby abolished.” Cal Penal Code 25-29(a)—Michigan’s Carpenter court reversed the legislative analytical approach to “there is no indication in § 21a that the Legislature intended to make diminished capacity an affirmative defense.” Carpenter, 464 Mich at 235-236.

The Carpenter court “did away with the diminished-capacity defense in total.” People v Tyson, 511 Mich 1080 (2023) (Cavanagh, J. dissenting).

Federal parallels ignored in Carpenter

How the Carpenter court reached its “no diminished capacity” result is striking in two ways.

First, the federal Insanity Defense Reform Act of 1984 substantively parallels MCL 768.21a. Neither mentions diminished capacity. A side-by-side comparison shows:

18 USC 17 Insanity Defense Reform Act of 1984 (as amended through 1986)

MCL 768.21a Persons deemed legally insane; burden of proof (as amended through 2014, replacing “mental retardation” and “mentally retarded” with less-stigmatizing terms)

(a) Affirmative Defense.—   It is an affirmative defense to a prosecution under any Federal statute that, at the time of the commission of the acts constituting the offense, the defendant, as a result of a severe mental disease or defect, was unable to appreciate the nature and quality or the wrongfulness of his acts. Mental disease or defect does not otherwise constitute a defense.     (b) Burden of Proof.—   The defendant has the burden of proving the defense of insanity by clear and convincing evidence.

(1) It is an affirmative defense to a prosecution for a criminal offense that the defendant was legally insane when he or she committed the acts constituting the offense. An individual is legally insane if, as a result of mental illness as defined in section 400 of the mental health code, 1974 PA 258, MCL 330.1400, or as a result of having an intellectual disability as defined in section 100b of the mental health code, 1974 PA 258, MCL 330.1100b, that person lacks substantial capacity either to appreciate the nature and quality or the wrongfulness of his or her conduct or to conform his or her conduct to the requirements of the law. Mental illness or having an intellectual disability does not otherwise constitute a defense of legal insanity.   (2) An individual who was under the influence of voluntarily consumed or injected alcohol or controlled substances at the time of his or her alleged offense is not considered to have been legally insane solely because of being under the influence of the alcohol or controlled substances.   (3) The defendant has the burden of proving the defense of insanity by a preponderance of the evidence.

And second, a solid line of federal court decisions was decided pre-Carpenter recognizing that the parallel Insanity Defense Reform Act of 1984 does not prevent a federal defendant from maintaining a diminished capacity as a failure of specific-intent-proof defense. In other words, the diminished-capacity defense remains viable in federal cases.

• United States v Frisbee, 623 F Supp 1217 (ND Cal, 1985)
• United States v Pohlot, 827 F2d 889 (CA 3, 1987), cert denied, 484 US 1011 (1988)
• United States v Gold, 661 F Supp 1127 (DDC, 1987)
• United States v Bartlett, 856 F2d 1071 (CA 8, 1988)
• United States v Twine, 853 F2d 676 (CA 9, 1988)
• United States v Newman, 889 F2d 88, n 1 (CA 6, 1989)
• United States v Fazzini, 871 F2d 635, 641 (CA 7, 1989), cert denied, 493 US 982 (1989)
• United States v Cameron, 907 F2d 1051 (CA 11, 1990)
• United States v Marenghi, 893 F Supp 85 (D Me, 1995)
• United States v Gonyea, 140 F3d 649, n 3 (CA 6, 1998)

Without explanation, Michigan’s Carpenter outcome was directly contrary to strong, earlier federal precedent interpreting substantively parallel language.

The 2001 Carpenter decision never mentioned or acknowledged the parallels to the federal Insanity Defense Reform Act of 1984 language.

And the Carpenter majority never mentioned any of the later (but pre-Carpenter) federal decisions recognizing that the diminished-capacity defense remains viable even after the similar 18 USC 17’s enactment.

The Carpenter dissent gave the federal parallels short mention near the end of its 18 pages.

Twelve years after Carpenter was decided, Justice Ginsburg (for a unanimous Supreme Court of the United States) suggested that Carpenter “was a reasonable interpretation of the language of a controlling statute.” Metrish v Lancaster, 569 US 351, 366, 368 (2013). Importantly, however, Metrish hinged on other procedural concerns and did not involve a direct Carpenter challenge. Even though Metrish included no analysis supporting its Carpenter characterization, its “reasonable interpretation” portrayal is an interesting wrinkle in the discourse.

The path to revisiting Carpenter and the diminished-capacity defense

Fast forward to recent years. The question has been when the Michigan Supreme Court would revisit Carpenter, not whether.

In a July 14, 2023 order in People v Tyson, four justices agreed that Carpenter was wrongly decided. People v Tyson, 511 Mich 1080 (2023) (Clement, C.J., concurring) (Cavanagh, J., dissenting, joined by Welch and Bolden, JJ.). Justice Cavanagh “urge[d] future practitioners to file motions in the trial courts seeking to admit diminished-capacity evidence. Although these motions will be invariably denied, they will satisfy preservation requirements and provide this Court an opportunity to review this issue . . . .”

The wait would not be long.

A diminished-capacity motion was filed in the Ottawa County Circuit Court four months later in the pending case People v Cinecca Madison (Case No. 22-45611-FC). The circuit court denied the motion on January 10, 2024 (as now-Chief Justice Cavanagh predicted). The Court of Appeals denied the motion for an interlocutory appeal on May 10, 2024, and an application for leave to appeal to the Michigan Supreme Court followed. The Supreme Court’s October 30, 2024 order stayed the Ottawa court proceedings, directed oral argument to be scheduled on the application, and ordered the parties to brief “(1) whether People v Carpenter, 464 Mich 223, 241 (2001) was correctly decided . . . .”

And as the Michigan Supreme Court revisits Carpenter when considering Cinecca Madison’s diminished-capacity argument, the Court also has abeyed at least four other pending applications for leave to appeal raising the same question (Docket Nos. 167621 (from Kalamazoo County), 168184 (from Genesee County), 168292 (from Benzie County), and 168324 (from Livingston County)).

Stay tuned for the October 9, 2025 People v Madison (167120) argument and what will follow.