I should add that to your original post given how obviously pro-business the Republicans were from the 1890s on (with the sole exceptions of TR and Taft) it’s kind of amazing that liberal Republicans managed to limp on into the 60s. I wonder if they maintained some kind of vague lingering hope that they could retake the party and possibly force a realignment where the Democrats would nominate a Dixiecrat in response until 1964 when it must have become obvious they had no future in the party.
In New York City, liberal Republicans were often Republicans just because Democrats were controlled by Tammany Hall.
