Massachusetts prosecutors are hard core when it comes to gun crime. As well they should be. But there are limits. Specifically, you gotta prove someone did something before you can sentence them for doing it. “The decision came in the case of Martin O’Brien and Arthur Burgess, who were charged in connection with a failed robbery of an armored car carrying $2 million in the Boston area in 2005,” the AP reports. “O’Brien and Burgess were indicted on several counts, including carrying a machine gun [an AK-47] in the commission of a crime. Federal prosecutors dismissed the machine gun count because they believed they could not prove it to a jury beyond a reasonable doubt. But they asked the judge to consider the machine gun charge, and the related 30-year prison term, in sentencing the defendants. The judge refused, the federal appeals court in Boston agreed with the judge and the government appealed the case to the high court.” And the Supremes told them to go pound sand. As well they should do. [Read the Court’s full decision on the UNITED STATES v O’BRIEN here.]