Both of you are correct. "White" as a political signifier does find plenty of usage in pre-20C writings and discourse (stuff like Thomas Carlyle's "Occasional Discourse on the Negro Question" for example), but it was hardly a point of primary ethnic identity -- Europeans were far more likely to identify as "Anglo-Saxon", "Spaniard", "Swede", etc. And there was certainly a good deal of ethnic strife between various White groups, both in Europe and in the European diaspora in the USA and elsewhere.
However, "White people" do have a legal definition, one that has been used in Western legal language and exacerbated by post-1960s ethnic grievance politics. "White" is simply the contraposition to "person of colour" or "minority". I don't think it matters that "white" identity is not historical - Whites today are an actual group with loose ethnic relatedness and what should be strong shared political interests.
See for example Canada's definition of a "Visible minority": "persons, other than Aboriginal people, who are non-Caucasian in race or non-white in colour." That's pretty clear.
> You can't even go back a single century before your pan-European notion of "white" identity breaks down. English-descended people refused to consider Spanish and Italian-descended people as "white".
However, "White people" do have a legal definition, one that has been used in Western legal language and exacerbated by post-1960s ethnic grievance politics. "White" is simply the contraposition to "person of colour" or "minority". I don't think it matters that "white" identity is not historical - Whites today are an actual group with loose ethnic relatedness and what should be strong shared political interests.
See for example Canada's definition of a "Visible minority": "persons, other than Aboriginal people, who are non-Caucasian in race or non-white in colour." That's pretty clear.