Eugenics and Progressives were usually one and the same, which is ironic, because to hear it told today, anti-miscegenation was something that conservatives were against. Actually, it was liberals, and Progressives in particular–and certainly eugenicists!–that were against the intermarriage of blacks and whites, and for that matter, whites and any other race, too. One must bear in mind that there was such a thing as Republican Progressive, too. This post will provide quotations by eugenicists attesting to the fact that anti-miscegenation was perceived by them not in ‘racists’ terms… but as simple scientific conclusions.
From Madison Grant in his Passing of the Great Race:
The prevailing lack of true race consciousness is probably due to the fact that every important nation in Europe as at present organized, with the sole exception of the Iberian and Scandinavian states, possesses in large proportions representatives of at least two of the fundamental European subspecies of man and of all manner of crosses between them. In France to-day, as in Caesar’s Gaul, the three races divide the nation in unequal proportions.
In the future, however, with an increased knowledge of the correct definition of true human races and types and with a recognition of the immutability of fundamental racial characters and of the results of mixed breeding, far more value will be attached to racial in contrast to national or linguistic affinities. In marital relations the consciousness of race will also play a much larger part than at present, although in the social sphere we shall have to contend with a certain strange attraction for contrasted types. When it becomes thoroughly understood that the children of mixed marriages between contrasted races belong to the lower type, the importance of transmitting in unimpaired purity the blood inheritance of ages will be appreciated at its full value and to bring half-breeds into the world will be regarded as a social and racial crime of the first magnitude. The laws against miscegenation must be greatly extended if the higher races are to be maintained.
It must be borne in mind that the specializations which characterize the higher races are of relatively recent development, are highly unstable and when mixed with generalized or primitive characters tend to disappear. Whether we like to admit it or not, the result of the mixture of two races, in the long run, gives us a race reverting to the more ancient, generalized and lower type. The cross between a white man and an Indian is an Indian; the cross between a white man and a Negro is a Negro; the cross between a white man and a Hindu is a Hindu; and the cross between any of the three European races and a Jew is a Jew.