A quarter-century ago, bipartisan majorities in Congress had come to understand that the federal sentencing system was, in today’s parlance, “broken.” Sentencing was rife with irrational disparity, principally because each judge could sentence as he saw fit—through the prism of his own temperament, experience, or even mood. judges did not have to follow any uniform sentencing standards, or even proceed under any established theory as to what sentencing was supposed to accomplish. Appellate review of sentencing was virtually non-existent....