While I would not at all wish to return to ethnic homogeneity (to the extent that ever existed), there was a very real downturn in immigration into the U.S. fro

While I would not at all wish to return to ethnic homogeneity (to the extent that ever existed), there was a very real downturn in immigration into the U.S. from FDR until LBJ. FDR was quite opposed to allowing immigration in, perhaps at least in part due to the very high unemployment that he was trying to address. The tight restrictions stayed in place for several decades.