Wasn’t being “white” legally required to vote in federal elections for most of US history? Were any of these groups ever prohibited from voting on the basis of not being “white”? I have never heard of that happening, have you? I think that would answer the question, since the government was actually in the business of determining “white”-ness at that time, and unless I’m mistaken, all of those groups were determined by the federal government to be “white”.

There was obviously negative sentiment towards various European groups, but they were always considered "white".

Quote from the article:

> Slavic peoples were considered to be people of an "inferior race" who were unable to assimilate into American society.[4] They were originally not considered to be "fully white" (and thus fully American), and Slavic peoples' "whiteness" continues to be a debate to this day, but most people consider them to be of Caucasian culture

The citations for this are horrible if you follow them.

edit:

One of them is just some 24 minute movie.

The other is false. The Immigration Act of 1924 did not establish any category of "inferior" races or countries.