Since the post on anti-miscegenation laws got a lot of attention, I was curious about analogs in the World Values Survey. There are two such questions of interest: Important for succesful marriage: Same ethnic background(D042) and Important for succesful marriage: Religious beliefs(D031) These data are skewed toward European nations. Below the fold are data are % who assert that same ethnic background is NOT very important, or that same religious beliefs are NOT very important. I will admit that the international pattern is surprising to me.
One essential issue here is that "same ethnic background" and "same religious beliefs" can be interpreted differently in various contexts. Perhaps in Finland we are talking about Swedes & Finns, while most British respondents assume that salient difference would be between whites and non-whites. Additionally, in Germany perhaps the religious difference would be between Protestants and Catholics, while in France Muslims outnumber Protestants, so the assumption is that you are referring to Muslims as the partner with the overwhelming Catholic majority. Finally, in some nations such as France there is some polarization between the secular and the traditionally religious. Let's compare the variables against each other:
Same Religion Not Very ImportantSame Ethnic Background Not Very Important
Austria47.3
Belgium54.7