I think America is doomed. You cannot save a country that has no "skin" barrier. We're just an amorphous protoplasmic economic system. There is no way, in Hell, to make this country white. You cannot stop them from coming here because they need to be forcefully stopped. A giant impenetrable wall does this. An EXTREMELY well staffed, NON-VOLUNTARY (drafted) National Guard that SWEEPS SWEEPS SWEEPS SWEEPS over the borders CONSTANTLY...or you get a million browns every year.
The only other thing I can think of now is to remove their incentive to come. Punish business owners who hire them with some of the most extreme shit imaginable. Like straight up life in prison for hiring illegals.