All parties either have some susceptibility to pressure or will die being insusceptible. Goldwater, if elected, would’ve been forced down the same road or suffered the consequences. LBJ’s coopting of civil rights merely gave him the time necessary to kill enough leaders that progress was minimized.
Hugely disagree with this. The Parties are subject to very different pressures as a result of their target audiences and core demographics: the Democratic voterbases of the sixties were far more open to the provisions of the Civil Rights Act than the Republican voterbase. The pressures are not the same.
And quite aside from this, history is utterly littered with mass movements which have been denied and eventually overpowered by entirely unsympathetic ruling powers.
Perhaps a few decades later, the pressures would have been impossible to suppress, even for the Republicans. That's decades more of segregation, lost livelihoods, un-investigated assaults, hiring discrimination, etc. In this difference, that's the difference caused by an electoral outcome, in which the lesser evil is not good by any stretch, but merely
better.