A lot of people are talking about this Tweet by historial Jon Meacham:
America should “build a wall of steel, a wall as high as Heaven" against the flow of immigrants.--Georgia Gov. Clifford Walker, at a 1924 convention of the Ku Klux Klan, then a powerful force at a time of strain for the white working class. #PastIsPrologue— Jon Meacham (@jmeacham) January 9, 2019
I went looking for the original, and found it quoted in Meacham’s 2018 book The Soul of America: The Battle for Our Better Angels.
It turns out that Georgia Governor Clifford Walker was talking about white immigrants from places like, say, Italy. (The wall was purely metaphorical.) He was concerned that they didn’t believe in, or have any experience with, democracy. You know what kind of people Italians were in the 1920s, politically speaking? They were Fascists.
The Second Ku Klux Klan, of the 1920s, while a quasi-secret society, was fairly mainstream, and wildly popular in many places. The voting population of Georgia supported Walker. And as for his metaphorical wall, that same year Congress passed the famous Immigration Act of 1924 (The Johnson-Reed Act), which restricted immigration from, among other places, Southern Italy.