Just to clarify, you're espousing the Great Replacement Theory here, correct?
That (conspiracy) theory pertains specifically to France, and Europe more generally w.r.t. Muslim immigration. It gets mentioned over here but it’s not a US thing.
It's metastasized and is very much a US thing, now. It hearkens back to the old white supremacist belief that Jewish elites are hoodwinking white people/culture/etc and replacing them with black people/culture/etc, for example. Similarly shaped ideas existed for hundreds of years in the US.
Immigrants are the electorate and have always been. *They* are what make America great, not some racist, talentless bums who believe they are entitled to an entire nation by virtue of their ancestry.
Poppycock. Complete, Orwellian inversion of the meaning of a nation.