Is an insanity defense, as such, constitutionally required?  Idaho has decided no, although it still allows a defense of a mental condition which negates an element of the offense.  Today the U.S. Supreme Court declined to review a claim that this is unconstitutional.  Justice Breyer, joined by Justices Ginsburg and Sotomayor, dissented from the decision not to take the case up (not necessarily with the merits of the state court's decision).  The case is Delling v. Idaho, 11-1515.

Which provision of the Constitution of the United States removes this decision from the legislatures of the states and assigns it to the federal judiciary?  Justice Breyer "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."  Once again, the oxymoron of "substantive due process" rears its ugly head.  All the way back to Dred Scott, the term "due process," which quite obviously refers to process and not substantive law, has been used for the Court's most illegitimate decisions.  It's good that they passed on this one.