In a ruling today in Rogers v. Dzurenda, a divided Ninth Circuit panel holds that a man convicted, on overwhelming evidence, of three brutal murders in 1980 is entitled to habeas relief on the ground that counsel provided ineffective assistance on his insanity defense. Some excerpts from Judge Mark Bennett’s dissent (citations omitted):

The majority characterizes Mark Rogers’s 1980 Nevada triple murder trial as a battle of the experts. In its view, the search for “cumulative prejudice” centers on the testimony of one expert who defense counsel failed to call as a witness and other experts who defense counsel should have better prepared. That narrative, however, obscures reality.… [T]he facts left little room for masterful counsel, much less merely adequate counsel, to have proven that Rogers was legally insane when he committed the killings.…
Rogers was not prejudiced by counsel’s performance. Although defense counsel could have done a better job, even a better presentation of the NGRI [not-guilty-by-reason-of-insanity] defense would have been very unlikely to succeed. “Under Nevada law, insanity is an affirmative defense which the presumedly sane defendant must prove by a preponderance of the evidence.” The inquiry looks at a defendant’s sanity when the offense is committed. As for the content of the defense, Nevada applies the M’Naghten rule, under which a defendant can rebut the presumption of sanity only by showing that he did not understand “the nature and quality of [his] acts,” had no “capacity to determine right from wrong,” or did not know “whether [he] was doing wrong when [he] committed the crime.” Under this test, “[l]egal insanity is not circumscribed in meaning or purpose by medical criteria concerning human psychosis,” and so “[t]he presumption of sanity is not rebutted merely by a history of prior institutional commitments or diagnoses of mental deficiency or derangement.”
Even a perfectly presented insanity defense, with additional and better prepared experts, would have been unlikely to rebut the presumption that Rogers was sane. The sequence of Rogers’s actions preceding, during, and after the killings confirmed that he understood he was killing the Strodes and that he understood that killing the Strodes was wrong. Yet in granting habeas relief, the district court [Judge Gloria Navarro] hardly engaged with the evidence the prosecution presented or the strength of its case.