Question

A "nativist" of the late-1800s would have been MOST likely to support

Answer 1

Nativism is political azenda of advertising the interests of old residents against those of immigrants which includes immigration-restriction measures.

Studies of scholarly nativism is a basic term technically.  

Those who hold this political view however don't typically accept the label.  

Dindar (2009) wrote "nativists don't consider themselves as nativists.  

For them it is a negative word and they thought themselves as 'Patriots'".