In the wake of World War II, 74 members of the Nazi SS were accused of a war crime--soon to be known as the Malmedy Massacre--in which a large number of American prisoners of war were murdered during the Battle of the Bulge. All of the German defendants were found guilty and more than half were sentenced to death. Yet none was executed and, a decade later, all had been released from prison. This outcome resulted primarily from the dogged efforts of...