Their goal seems to be:
“You can’t have oppression by an ethnic majority if you don’t have an ethnic majority.”
So not immediately, no. After all, Hillary Clinton was their presidential candidate. But it does seem like the plan is “let’s defeat white supremacy by making the whites a minority,” which might work, or might not work.
I live in a world where democrats periodically talk about how eventually all those darn old racist white redneck men will die off and America will be significantly more racially diverse, and the GOP needs to “get with the times, grampa”, so to speak. It’s also a world where the democrats describe opposition to immigration as fundamentally rooted in racism, and just last week I was arguing with someone I knew IRL that said America has an obligation to take in all peoples because it is on land stolen from Native Americans (and therefore not only can immigration not be decreased but we can’t even have limits on countries which lack functioning governments to vet newcomers).
This is, of course, ignoring all the various other progressive leftists grouped in with the democrats that are much less, hm, “gentle” and just looking at the mainstream of the party. (Again, Hillary “super predators” Clinton was their candidate, not their opinion columnists.)
Anyhow, “mass migration” is also a bit of an overstatement regarding current immigration policies, so “culture war against the country’s ethnic majority” is also a pull in the other direction for contrast with where they are right now, depending on just how you define culture war.
Though… once the demographics change, do you think they’ll actually stop trying to fight white supremacy? Or will they just change focus, like how women are the majority of undergraduate university students, but we mostly hear about how STEM needs more women (even though the fields of biology also flipped majority women recently, IIRC)?
And perhaps more importantly, do the Republican Party and their voters believe it will stop?