In the modern day, it feels to me like "Whiteness" is expanding to include African-Americans. The strongest dividing line again seems to be between established American ethnicities and recent immigrants, and African-Americans clearly belong to the former, in a way that Salvadorans or Pakistanis may not.
Lmao. Summer of the 2020 completely proves this false.
It's true if you think of "whiteness" as "the American cultural mainstream", and really has been long before BLM became a thing.
That would be an unspeakably stupid definition and it wouldn't be an accurate statement even then. Sitcoms and television commercials had more black people in them forty-five years ago than they do now.
Anyway, no, the definition of whiteness has not expanded. The only way to believe that it has is if you think that white people definitionally cannot experience ethnic prejudice from other white people, which is also stupid. During the late nineteenth and early twentieth centuries, naturalization in the United States was limited by law to white and black people, which is to say that it is very easy to understand which people were viewed as white at the time. Italians, Jews, and Arabs all naturalized in enormous numbers because they were white. That they weren't allowed into country clubs doesn't change that. Indians and Chinese were not considered white then (see
U.S. v. Bhagat Singh Thind and
U.S. v. Wong Kim Ark) just as they are not now.
If anything, the definition of whiteness has contracted over time. One example is the planned "Middle Eastern" category on the Census, which would formalize the notion that Arabs, a group that has always legally and culturally been white in this country, are now non-white.
I know that Hispanic is not a race on the US Census, but even white Hispanics nowadays are often regarded as non-white. Dolf Luque of Havana had a long and successful career pitching in the major leagues between 1914 and 1935, a period of time when organized baseball was white-only. As I understand it, reference was occasionally made in the American press to his patrician Spanish ancestry, but because he looked white there was no serious anxiety about his whiteness. Mike Gonzalez, also of Havana, caught in the major leagues between 1912 and 1932 and later became manager of the St. Louis Cardinals. This would not have happened if his whiteness had been in question.
Asians will not "become white" over time because there is no evidence of this process ever having happened in this country's history. Those that intermarry with whites may have white descendants, but only if those descendants are sufficiently white-looking that they lack obvious Asian ancestry.