This educational guide is based on the linked primary sources. It is not a Court publication, is not affiliated with the Court, and is not legal advice.
In brief
Overview
According to Sarah Schrup, on behalf of the Petitioner, the petitioner argues that Kansas’s statutory approach to the insanity defense, which eliminates a moral‑capacity test, violates the Fourteenth and Eighth Amendments.
According to United States (Amicus), according to United States (Amicus), the United States amicus states that the petitioner has not met the burden of showing that substantive due‑process principles override Kansas’s mens‑rea test of insanity.
Background and question before the Court
What each side argues
Petitioner
According to Sarah Schrup, on behalf of the Petitioner, kansas’s law scrubs moral capacity from criminal law, running afoul of the Fourteenth and Eighth Amendments.
According to Petitioner (Ms. SCHRUP), according to Petitioner (Ms. SCHRUP), the mens‑rea approach “scrapes out the why,” removing the underlying motivation fueled by mental illness.
According to MS. SCHRUP, the petitioner acknowledges that the record does not contain data on how often insanity defenses are raised or successful in the 46 states that retain the rule.
According to MS. SCHRUP, the petitioner argues that the line should not be drawn at punishment.
Respondent
According to United States (Amicus), according to United States (Amicus), the United States amicus supports the respondent, stating that the petitioner bears the burden of establishing that substantive due‑process principles override Kansas’s mens‑rea test and has not carried that burden.
According to Elizabeth B. Prelogar, Assistant to the Solicitor General, Department of Justice, Washington, D.C.; for the United States, as amicus curiae, supporting the Respondent, elizabeth B. Prelogar, Assistant to the Solicitor General, filed an amicus brief supporting the respondent.
What happened at oral argument
Justice Kagan asked how often insanity defenses are raised and how often juries actually find insanity in the 46 states that retain the rule.
Justice Gorsuch asked how far the insanity defense must be extended as a matter of due process – whether to all homicides, all felonies, or where the line should be drawn.
According to Justice Sotomayor, justice Sotomayor questioned whether the mens‑rea test takes away the excusing of a person who, historically, would have been considered a lunatic with no volition to fight back.
Justice Alito asked why the petitioner is arguing for a separate insanity defense tied to M’Naghten, noting that historically insanity was linked to mens‑rea and applied categorically in every case.
According to Justice Alito, justice Alito further questioned whether the 18th‑century understanding of the human mind, which lacked modern psychiatry, should affect the analysis of insanity defenses.
What the Court decided
Why it matters
Terms to know
No glossary terms are available for this guide.
Primary sources
Read the source materials on the official site or open the immutable repository copy used for this guide.
- 80e23875e50e2bd22573-r1-1d40d0ab8170cbb6.pdforal argument transcript
Guide generated September 27, 2026. Automated validation accepted this version.