In the populist era proper, William Jennings Bryan (whom FDR considered the founder of the "modern" Democrat party) was extremely popular in the South. While he wasn't a screaming white racist (he was more indifferent to the plight of Blacks) his supporter "Pitchfork Ben" Tilghman of South Carolina mixed populism and white racism into a homogenized brew. Georgia's Tom Watson actually appealed to Blacks as a young populist politician but became a racial demagogue later (as a Democrat).
Even during the New Deal era Roosevelt was allied with racist Southern whites who often uttered their racial hatred in the name of "the poor." Bilbo and Rankin of Mississippi are two examples here. Reynolds of North Carolina seems to have been an exception to this, as was Long, though Long actually raised the specter of "Negro domination" more than most people today realize (this was in order to keep people from voting Republican, of course).
Meanwhile, in the "left wing" Midwest you had the Germanophilia of the two world wars and "America First" isolationism (something Southern conservatives didn't share in, though today's neo-Confederates do). The Midwest is of course largely ethnically German and Chicago was the center of the America First movement Charles Lindbergh, the son of a "left wing" populist congressman from Minnesota, was its most famous and visible leader.
As an aside here, it's ironic that Chicago Germans, who are regarded as practically demigods by the "palaeos" for their opposition to American entry into World War II, were at least in part lineal descendants of the huge Chicago German immigrant community who supported Abraham Lincoln so strongly. Yet those Chicago Germans are regardes as "Communists" by "palaeos!" I think they would like to imply that all the pro-Lincoln Germans were Jews!
A great deal of the populist left was pacifist and this is where the shift occurred. In the teens and twenties it was "left wing" to oppose war. Suddenly in the late thirties and early forties it was "right wing!" So a lot of the "right wing isolationists" of that era were actually simply left wing pacifists who simply maintained their original position on war rather than changing it! But that's something the libs don't want you to know. Even some of the most allegedly "reactionary" characters of the New Deal era (Father Coughlin, Townshend) were actually "left wing" on economic issues by any honest standard.
And of course, to this very day we have "radical right wingers" whose rogues gallery is identical to that of the left wing populists of the late nineteenth century: the Rockefellers, the Morgans, the Mellons, the Whitneys, etc. Only while the old populists considered them capitalist pigs, today's "palaeos" consider them "the real power behind Communism!" Amazing--the ideologies of both sides have changed 180 degrees, but the characters on both sides are the same!
Of course populist anti-capitalism has its roots in opposition to the bourgeois world created by the French Revolution and a yearning for a pre-capitalist "organic society." Both John C. Calhoun in America and Metternich in Europe assumed the role of protectors of the lowest classes from the predations of the recently unleashed (by the liberalism of the French Revolution) laissez-faire economic system. Even on Free Republic some Catholic posters voice this position. (No offense to you, elcid. I'm a Theocrat as well.)
Pinging to wideawake so he can correct my mistakes and make additional points.
Excellent post! I’ve learned a great deal about populism(s).
In World War I German-Americans suffered the suspicions we have read about (before there were Freedom Fries there was Liberty Cabbage). But I also read that Ashkenazic Jews in America were very pro-Kaiser, the old “Germans first, Jews second”) stance that the more Jews acted like Germans the more accepted they would be. Very much generalizing here, but apparently Jews in WWI did not regard Germany as an existential threat. That would later change.