One of those terms I’ve never understood - what’s wrong with being “nativist?”
Old "immigrantist" smear .... it means, anyone who didn't like rich guys importing bulk labor to undercut their wages.
Also, anyone who wasn't cool and down with letting in people who couldn't speak the language, didn't know anything about the country or the culture.
They were maybe right about their reluctance: after 1848, we got boatloads of German and German Jewish socialists who were statist as hell and hadn't the foggiest idea about "human rights", "citizens' rights", or anything else, to whom government was supposed to be a Leviathan of social services. Never lived in the countryside, never learned to be American, just stayed in town on the East Coast and dickered with ward heelers for "services".
In 1928, they took over the Democratic Party.