The decline in private sector unions in America is well documented, but some unions have bucked this trend, most notably the 2.1 million member Service Employees International Union. Its former president liked to say: "We use the power of persuasion first. If it doesn't work, we try the persuasion of power." The targets of SEIU's corporate campaigns find themselves on the defensive and, tied to traditional public responses, are often flummoxed by the intensity and thoroughness of the SEIU's efforts. There is, however, a new arrow in the quiver that can be used by firms that are being attacked...