What of the native born who are culturally conservative, that is to say, resistant to cultural advancement. Certainly when added to immigrants they have a heavy effect on the national character. There is more to cultural diversity than just foreign born. There are quite a number of native born cultures as well.
Immaterial, my friend. Jews, eastern Europeans, Asians, Africans, and South Americans have already influenced our culture, and that will only continue.
As the Catholic minority and the non-religious minorities continue to negate the white right evangelical influence, demographic cultural change will continue.
No one, Publius, wants to live in a cultural world the equivalent of the 1950s.