Over dissent of three Justices, SCOTUS refuses to review Idaho's restriction of insanity defense

As reported here at SCOTUSblog, the Supreme Court returned to work today with an orders list that included no new certiorari grants and a few notable denials of cert.  One such denial generated a multi-Justice dissent: "Among the Court’s more significant orders denying review, it refused to hear a claim that the Constitution requires states to allow an accused an opportunity to use insanity as a defense to a criminal charge.   The case of Delling v. Idaho (11-1515) was denied over the dissents of three Justices — Stephen G. Breyer, joined by Ruth Bader Ginsburg and Sonia Sotomayor."  Here are a few excerpts from Justice Breyer's dissent (with some quotes and cites eliminated), which in part explain why I am not troubled by this SCOTUS cert dodge:

Idaho provides that “[m]ental condition shall not be a defense to any charge of criminal conduct.” Idaho Code §18–207(1) (Lexis 2004). Another provision of the same statute provides, however, that the above restriction is not “intended to prevent the admission of expert evidence on the issue of any state of mind which is an element of the offense.” §18–207(3). And the Idaho courts have made clear that prosecutors are still required to prove beyond a reasonable doubt that a defendant had the mental capacity to form the necessary intent. Thus, in Idaho, insanity remains relevant to criminal liability, but only in respect to intent. Insanity continues to have relevance at sentencing as well. A court must “receiv[e]” evidence of mental condition at sentencing and, if mental condition proves to be a “significant factor,” must consider a string of issues deemed relevant to punishment, including, notably, “[t]he capacity of the defendant to appreciate the wrongfulness of his conduct.”  Idaho Code §19–2523 (Lexis 2004).  In addition, if the court imposes a prison sentence on a person who “suffers from any mental condition requiring treatment,” Idaho law appears to mandate that “the defendant shall receive treatment” in an appropriate facility.  See §18–207(2).

Still, the step that Idaho has taken is significant.  As that State’s courts recognize, it may allow the conviction of persons who may be insane by some former insanity test or medical standard, but who nevertheless have the ability to form intent and to control their actions. That is, the difference between the traditional insanity defense and Idaho’s standard is that the latter permits the conviction of an individual who knew what he was doing, but had no capacity to understand that it was wrong....

I would grant the petition for certiorari to consider whether Idaho’s modification of the insanity defense is consistent with the Fourteenth Amendment’s Due Process Clause.

In the lingo of many criminal law theorists, the insanity defense is classic "excuse" defense to criminal responsibility, not a "justification" defense.  Though I think the Constitution might well limit the authority of states to eliminate entirely certain justification defenses (like, for example, self defense), I am not quite sure why a state should not be allowed to get rid of certain excuse defenses as long as it preserves some role for excuse considerations at sentencing.  Indeed, ever the sentencing geek, I have long believed it might be wise for many theoretical and practical reasons — as well as constitutionally permissible — to eliminate all pure excuse defenses in order to turn them into (required) sentencing factors.

Criminal law theorists and/or long-time readers might rightly conclude that my general disaffinity for excuse defenses is just one part of my general disaffinity for retributivist theories of punishment (as well as my view that guilt determinations should be principally concerned with offense conduct and that sentencing is the place for broader consideration of offender characteristics).  I fully understand, though do not find compelling, a certain retributivist viewpoint that a just system of criminal punishment must preserve some traditional form of the insanity defense to criminal liability.  Consequently, I am inclined to view this notable denial of cert as an indication that there are not currently four Justices drawn to the notion that the Constitution's Due Process Clause includes certain retributivist criminal justice fundamentals.

An interesting follow-up question to this cert denial for even utilitarian-minded folks is whether and when the diminution of mental condition considerations at sentencing might present Eighth Amendment issues.  Especially in the wake of the Supreme Court's recent work in Graham and Miller, it is intriguing to consider a potential Eighth Amendment challenge to any mandatory LWOP sentence given to a clearly insane person in a state like Idaho that has precluded raising an insanity defense at the guilt stage of proceedings.  Ever the fan of a robust Eighth Amendment jurisprudence, I might be more drawn to this kind of constitutional claim than to one based in the Due Process Clause.