Commonwealth v. McLaughlin

(concurring, with whom Abrams and Lynch, JJ., join). I would hold that in cases to be tried after today, the burden will be on a criminal defendant to prove his insanity by a preponderance of the evidence. I would abandon our practice, which we approved by divided vote in Commonwealth v. Keita, 429 Mass. 843 (1999), of stating simultaneously that the Com*521monwealth has the burden of proving a defendant’s sanity beyond a reasonable doubt and that the jury may rely, in determining whether the Commonwealth has met that burden, on what we have called the “presumption of sanity.”

The defendant’s…