The theory was eugenics, and its history is so dreadful --- and, to those who were caught up in it, so embarrassing --- that it is now rarely discussed. But it is a story that should be well know to every citizen, so that its horrors are not repeated.
The theory of eugenics postulated a crisis of the gene pool leading to the deterioration of the human race. The best human beings were not breeding as rapidly as the inferior ones --- the foreigners, immigrants, Jews, degenerates, the unfit, and the "feeble minded." Francis Galton, a respected British scientist, first speculated about this area, but his ideas were taken far beyond anything he intended. They were adopted by science-minded Americans, as well as those who had no interest in science but who were worried about the immigration of inferior races early in the twentieth century --- "dangerous human pests" who represented "the rising tide of imbeciles" and who were polluting the best of the human race.
The eugenicists and the immigrationists joined forces to put a stop to this. The plan was to identify individuals who were feeble-minded --- Jews were agreed to be largely feeble-minded, but so were many foreigners, as well as blacks --- and stop them from breeding by isolation in institutions or by sterilization.
As Margaret Sanger said, "Fostering the good-for-nothing at the expense of the good is an extreme cruelty … there is not greater curse to posterity than that of bequeathing them an increasing population of imbeciles." She spoke of the burden of caring for "this dead weight of human waste."
Such views were widely shared. H.G. Wells spoke against "ill-trained swarms of inferior citizens." Theodore Roosevelt said that "Society has no business to permit degenerates to reproduce their kind." Luther Burbank: "Stop permitting criminals and weaklings to reproduce." George Bernard Shaw said that only eugenics could save mankind.
There was overt racism in this movement, exemplified by texts such as "The Rising Tide of Color Against White World Supremacy" by American author Lothrop Stoddard. But, at the time, racism was considered an unremarkable aspect of the effort to attain a marvelous goal --- the improvement of humankind in the future. It was this avant-garde notion that attracted the most liberal and progressive minds of a generation. California was one of twenty-nine American states to pass laws allowing sterilization, but it proved the most-forward-looking and enthusiastic --- more sterilizations were carried out in California than anywhere else in America.