Officially the US census defines "White" as "A person having origins in any of the original peoples of Europe, the Middle East, or North Africa" [0]
However, the "Middle East, or North Africa" part seems rather disputed in American culture. Some Americans are happy to view the Middle Eastern and North African people (MENA for short) as "White", and some MENA Americans are happy to identify as "White". Other Americans disagree that MENA people count as "White", and some MENA Americans disagree with the application of the "White" label to themselves. [1]
The US Census Bureau proposed to add a separate MENA racial category to the 2020 US Census, [2] but later dropped the proposal, allegedly due to political pressure from the Trump administration [3]
Another issue is the status of Hispanic people. Approximately 65% of all Hispanic/Latino people in the US identify as "White" (that's what they put down on their Census forms), but I know from discussions I've had with Americans on this topic that some of them don't actually perceive "White"-identified Hispanic/Latino people as "White". And many US sources, e.g [4], claim that the US will become "minority white" around 2045; that is only true if one excludes "White Hispanics" from the category "White" – if one includes "White Hispanics" as "White", the US will likely still be majority "White" by the end of this century – but this just shows how even in official contexts "White Hispanics" are often not considered "really White".
Many other countries sidestep these kinds of issues by officially avoiding putting people into broad racial categories, and focusing instead on narrower ethnicity/nationality/ancestry categories (Nigerian, Mexican, Argentine, Irish, Italian, Chinese, Japanese, Iranian, Indian, Arab, Jewish, Kurdish, Tibetan, etc). But, viewing human diversity as coarse rather than fine-grained groups is deeply entrenched in American culture, and seems in the last few years to have become even more emphasised than it was in the past, so it appears unlikely that America will follow the example of any of these other countries any time soon.
