This GOP base you speak of, is white and aging, soon they will be irrelevant.
Mash your teeth all you want, but times are changing like they always do and a new base needs to be appealed to.
Millennials are just as big as the baby boomers, they are going to be a group to deal with. GenX like a bunch of on here, are stuck in the middle and there isn't very many of in the US population.
Non-hispanic whites are still 63% of the population. Blacks are ~13% and vote 9:1 Dem:GOP. Hispanics are ~13% and vote 3:1 Dem:GOP. It costs between 10x to 100x to get a middling voter enthused to vote relative to a base voter.
Influencing 1% of the white population to vote GOP provides as many voters as getting 5% of either black or hispanic populations. And that 5% of NAMs will be mostly from the middling, expensive-to-motivate part of the electorate. The further right you move in the GOP base the whiter the proportions. They are much cheaper dollar per vote-wise.
Given that, plus basic algebra,
if the GOP wants to win anything in the near term, it will have to rally the base. If the GOP wants to stay relevant, it will stop all third world immigration, expel those already here, and implement policies that encourage affordable family formation so white Americans have more kiddos.
If the GOP wants to stay forever irrelevant, it should import more folk who will vote Dem/FSA in perpetuity.
The smaller the white population gets, the more it will move toward Lee Kuan Yew's position:
"In multiracial societies, you don't vote in accordance with your economic interests and social interests, you vote in accordance with race and religion."
----Lee Kuan Yew, first PM of SingaporeTaking a look at the nationalist parties in Europe, you'll see none are ideologically pure. A mix of capitalism and communitarianism, economics-wise. They already embody LKY's observation. Expect expulsions and violence. The first violence likely will be the ruling class warring on the nationalists and fellow citizens. The usual "frontlash" is propaganda(1), but the closer the nationalists come to power, the more likley the ruling class will use violence on the citizenry. Eventually the nationalists will come out on top. I think they will treat those they defeat as they were treated.
(1) See NYT after any outrage committed by NAMs or muslims so worried about a backlash, they libel the majority of the population.