[...] The U.S. labor movement's success in having open immigration outlawed in the 1920s set the stage for the stabilization of the U.S. working class and contributed to the subsequent CIO (Congress of Industrial Organizations) victories in the 1930s. At the same time, however, this U.S. labor movement "success" shut off what had been an essential social safety valve for Europe in the nineteenth century. It thereby transformed the terrain on which workers' movements operated in Europe and, according to E. H. Carr (1945), helped set the stage for the defeat of European labor movements and the rise of fascism.