By 1963-64 they had in effect taken over the GOP and had all but guaranteed the presidential nomination for Barry Goldwater. Rockefeller, on the other hand, had his own problems. He raised taxes shortly after his election in '58. In 1962, he ran for reelection with a campaign promise not to raise taxes in his next term, a promise that lasted less than a year. When he ran for a third term in 1966, he pledged not to seek the presidential nomination in 1968.
Events have a way of changing things.
In February of '68, with the collapse of the candidacy of Michigan Gov. George Romney, moderate Republicans begged Rocky to get into the race. But in a surprise announcement three weeks later, Rockefeller declared he would not seek the nomination, saying that Richard Nixon had a nearly insurmountable lead in delegate strength. He added that he was open to a draft, but would not do anything to make it happen. Until that time, Rockefeller sidestepped specifics on national issues, including dealing with the Vietnam War. He later issued a peace-plan in which he said the war could end in six months.