I think most of what I said in this thread probably can't fit into the Overton Window, but I don't think it really needs to.
The argument for less mass migration should be made more along populist economic lines rather than cultural preservation lines.
A way to stop wage suppression, multi-lingual schools making it harder to educate, crowded hospitals, rising housing costs, the rise of automation meaning we need less low-end labor, environmental preservation, say oligarchs in both parties want it and are greedy, etc
That's basically what Coolidge did.