Andrew Beck has articulated a thick version of the assimilation of immigrants (rightly so, in my view) that harkens back to the spirit of Americanization that was prevalent from the Founding to roughly the 1960s. Louis Brandeis, a liberal and political ally of the detestable Woodrow Wilson, expressed this common idea of assimilation in his July 5, 1915, Americanization Day Speech:
What is Americanization? It manifests itself, in a superficial way, when the immigrant adopts the clothes, the manners and the customs generally prevailing here. Far more important is the manifestation presented when he substitutes for his mother tongue the English language as the common medium of speech. But the adoption of our language, manners, and customs in only a small part of the process. To become Americanized the change wrought must be fundamental. However great his outward conformity, the immigrant is not Americanized unless his interests and affections have become deeply rooted here. And we properly demand of the immigrants even more than this. He must be brought into complete harmony with our ideals and aspirations and cooperate with us for their attainment. Only when this has been done will he possess the national consciousness of an American.