Nixon is the best example of pragmatism--that is, doing things for political gain rather than for the good of society.
I think you're confusing Reagan's "pragmatism" for settling for less than he might have wanted. This doesn't mean he compromised principle, as his closest staff have maintained, even as late as now. Michael Deaver has said that Reagan's staff was pragmatic, but not Reagan.
Barry Goldwater, OTOH, was never pragmatic, could NOT get elected, and turned lefty in his later years. Go figure
You are correct, Barry did not win the presidency. But he was elected numerous times as an Arizona senator, and he set the stage for Reagan's elections. Many credit him for sowing the seeds for the conservatism of today.
The influence of both men of principle far outways the contributions of the pragmatic Nixon.
Barry " flipped " ( due to old age , his new wife , who later had his ear ? One two, or all combined ) and so, his " principles flew out of the window. Yes, I know that Goldwater has been enshrined as the one who made a Reagan presidency / the Conservative movement possible. I now have some doubts about this.
You can call what Reagan did , vis-a-vis the amnesty for ILLEGALS, and a number of other things, whatever you want ; it was still pragmatism ! Sematical arguements are more than a triffle silly.