I never know why people always act like the anti-Rockefeller faction was too strong for him to ever win, he was the respected governor of New York and widely popular. Although he was liberal, he was hardly ideological and even tried to put together a Rockefeller/Reagan ticket at the RNC in ‘68.
(1) His being governor of New York was part of the problem. New York, to much of the Republican Party outside the Northeast, meant Wall Street internationalism. (And of course to the South, increasingly important in the GOP, it meant civil rights liberalism.) It meant the force that had dominated the GOP for decades, and had led to the failed candidacies of Willkie and Dewey (and to Eisenhower, whose success was personal and went along with an actual decline of GOP strength on the non-presidential level during his administration). It was not the conspiracy-obsessed Robert Welch but the respected Senator Taft who bitterly said after Eisenhower's nomination, "Every Republican candidate for President since 1936 has been nominated by the Chase Bank."
https://books.google.com/books?id=-f9QDQAAQBAJ&pg=PT485 Of course "Chase Bank" meant the Rockefellers.
https://en.wikipedia.org/wiki/Chase_Bank
(2) The fact that Taft in 1952 had
almost defeated the very popular Eisenhower for the nomination gives some indication of how powerful conservative resentment of the "Eastern Establishment" had become. It only intensified in later years, for three reasons:
(a) the rise of a conservative
movement (something which Taft had never really had) centered on
National Review, Clifton White and William Rusher's "Syndicate" (which gained control of the Young Republicans years before Goldwater was nominated--in 1959 "at the YR convention in Denver, Rusher and White saw through the election of an alliance that was overtly anti-Rockefeller, anti-Eastern, and anti-liberal"
https://books.google.com/books?id=6vwvCgAAQBAJ&pg=PA1392), etc.
(b) the defeat of Nixon in 1960. Progressive and conservative Republicans could join forces behind him that year, but once he lost, it became commonplace for conservatives to blame his defeat on his being a "me too" candidate--his choice of Lodge for running mate and his "surrender" to Rockefeller in the "Treaty of Fifth Avenue"
https://en.wikipedia.org/wiki/Treaty_of_Fifth_Avenue were particularly blamed; and
(c) the increasing importance of the South and Southwest in the GOP. It would be difficult to overstate southern opposition to Rockefeller. In 1964, of the 278 southern delegates, 271 voted for Goldwater, and Goldwater's southern coordinator, John Grenier, claimed that 260 of them were "rock solid", meaning that they would have stayed with Goldwater even had he lost in California. (George Gilder and Bruce Chapman, *The Party That Lost Its Head*, p. 184.) In 1968, as I noted here, "The conservatives were more polite to him than they were in 1964, but he was still just as unacceptable. In particular, he had virtually no support in the South. Or rather, the only southern support he had was from the New Orleans Rockefeller for President group, led by a Tulane University history graduate student named Newt Gingrich...To show how hopeless Rocky's position in the South was, consider this: Kentucky was the most "northern" southern state; it had produced moderate Republicans like US Senators John Sherman Cooper and Thruston B. Morton. Yet Governor Louis Nunn told reporters in Miami, "Our delegates know that if they voted for Rockefeller down here they wouldn't be allowed off the plane back home." (Kabaservice, p. 243.) Rocky was also weak in the West, and hardly had the Midwest--or even *all* the delegates from the East--locked up either."
https://www.alternatehistory.com/forum/threads/ronald-reagan-in-1968.443980/#post-17038433
(3) There was indeed a de facto Rocky-Reagan alliance at the 1968 convention, for the purpose (almost achieved!) of denying Nixon the nomination on the first ballot. But as Geoffrey Kabaservice noted, "The Reagan-Rockefeller marriage at the convention would be strictly one of convenience. Rusher admitted that if Rockefeller actually received the GOP nomination, he would bolt to form a new party. Rockefeller was still anathema to conservatives, while Reagan was almost as unacceptable to GOP progressives as Goldwater had been in 1964. The implausibility of this left-right coalition left Richard Nixon in the center, exactly where he wanted to be."
https://books.google.com/books?id=ZlRpAgAAQBAJ&pg=PA241 https://books.google.com/books?id=ZlRpAgAAQBAJ&pg=PA242
I maintain that there was only one way for Rockefeller to become president, and that was through the vice-presidency. Nixon offered him the second spot in 1960 but (as expected) he declined; in 1968 there was serious talk of a Humphrey-Rockefeller ticket
https://www.alternatehistory.com/forum/threads/humphrey-rockefeller-ticket-in-1968.336723/; and of course when Rocky finally accepted the vice-presidency, Squeaky Fromme and Sara Jane Moore came very close to making him president...