I'm curious as to what you mean by this? Is this a Henry Ford or a Father Coughlin thing? Ford reprinted the Protocols but they were a Czarist Russian creation (btw, how nice that Russian influence ops are still a thing in our politics).
Coughlin had that blowtorch radio program but he was Catholic and not in sync exactly with Nazi ideology.
Do you mean that Detroit-based Germans were upset about the end of WWI and created the Dolchstoßlegende?