A contemporary usage of this metaphor was that of Ralph Waldo Emerson's private vision in 1845 of America as an ethnic and racial smelting-pot, a variation on the concept of the melting pot. S on the desirability of such intermixing, including that between white Protestants and Irish Catholic immigrants, were divided.
In Portuguese-speaking Latin America (i.e., Brazil), a milder form of caste system existed, although it also provided for legal and social discrimination among individuals belonging to different races, since slavery for blacks existed until the late 19th century.
The Nazi ban on interracial sexual relations and marriages was enacted in September 1935 as part of the Nuremberg Laws, the Gesetz zum Schutze des deutschen Blutes und der deutschen Ehre (The Law for the Protection of German Blood and German Honour).
The Nuremberg Laws classified Jews as a race, and forbade extramarital sexual relations and marriage between persons classified as "Aryan" and "non-Aryan".
Intermarriage occurred significantly from the very first settlements, with their descendants achieving high rank in government and society.
To this day, there are controversies if Brazilian class system would be drawn mostly around socio-economic lines, not racial ones (in a manner similar to other former Portuguese colonies).
There was already much opposition to the war effort.