To recycle an old post of mine:
"Albert Eisele and others have contended that had their positions been reversed in 1964, Hubert Humphrey and Gene McCarthy would have found themselves in similarly reversed positions in 1968. McCarthy was one of the most likely choices for Lyndon Johnson's running mate in 1964. He was a personal favorite of the Johnson's and a northern liberal, which provided a good balance to Johnson's more conservative Southern appeal, just as Humphrey did. He was articulate and had a genuine flair. Even more important, though, he was a Catholic, and was so at a time when LBJ was under considerable pressure to justify his *not* choosing Bobby Kennedy as his running mate. Nevertheless, as the convention neared it became clear that McCarthy was no longer being seriously considered by Johnson. When he felt that he was simply being manipulated by the Johnson machine, McCarthy broke with it. Many have, consequently, seen McCarthy's run for the presidency in 1968 as nothing more than a grudge match in response to this. If McCarthy *had* been chosen as Johnson's running mate, Humphrey would have remained in the Senate as the leading figure that he was. He thus would not have been forced by both personal and professional constriants into a position that many regard as his downfall, namely, of becoming the administration's leading spokesman for its involvement in Vietnam. Humphrey, as the theory continues,would have been free to be critical of the administration's policy in Vietnam, and McCarthy instead would have been faced with the extremely difficult position with which Humphrey actually ended up having to contend." Charles Lloyd Garrettson, *Hubert H. Humphrey: The Politics of Joy*
http://books.google.com/books?id=YRTeKY1xcVUC&pg=PA157
McCarthy was definitely a hawk on Vietnam in 1964. To quote Dominic Sandbrook in *Eugene McCarthy: The Rise and Fall of Postwar American Liberalism*, pp. 126-27:
"McCarthy himself, his mind on the vice presidency, had no doubt that the Gulf of Tonkin resolution was justified and necessary. 'The strength of America,' he wrote to his constituents, 'is not just the strength of its military power but also the strength of its reputation, honoring its word and keeping its commitment. All of these things were involved in the President's action, which has been sustained by the Congress.' On the television show *Face the Nation*, he said, 'It was a matter of responding to a direct attack on our ships. The escalation came from the enemy.' Johnson, McCarthy thought, must have no doubts about his vice president's commitment to the existing policy in Vietnam, His Minnesota friend Gerald Heaney recalled, 'He made it clear that he felt we were committed in Vietnam and we'd have to see it through to the end.' McCarthy added that his rival for the vice presidency, Hubert Humphrey, was more likely to abandon that commitment, telling Heaney, 'He might be inclined to tell the editor of the *New York Times* that he goes along with it because he has to but that we ought to be doing something different.' McCarthy even asked Heaney to point this out to Johnson himself...
"Even after his vice presidential hopes had been dashed, McCarthy's fidelity to the administration never wavered. 'I do not think we can simply withdraw our forces and abandon the people of South Viet Nam,' he wrote, dismissing the idea of neutralization. 'Our experience with a supposedly neutral Laos has been none too encouraging.' In a debate with his Republican opponent in Minnesota, he even refused to rule out an invasion of North Vietnam. At the end of the year he explained to a Minnesota clergyman that Johnson's policy was the best way of reconciling the twin goals of peace and containment: 'I supported the actions of the Eisenhower and Kennedy Administrations in this area, and beleive that the policy of the Johnson Administration in limiting the action to South Vietnam and keeping the use of force to a minimum is at least the best immediate policy.' In short, at the end of 1964 there was no reason to imagine that McCarthy would remain anything other than a wholehearted supporter of the American involvement in Southeast Asia."
http://books.google.com/books?id=wMqSzTPXl7QC&pg=PA126
It is of course true that most of the members of Congress who voted for the Gulf of Tonkin resolution and supported LBJ's Vietnam policy in 1964 had no idea that within a few years that would be half a million American soldiers in Vietnam. So it is certainly possible that McCarthy would "evolve" toward an increasingly anti-war position as vice president the way he did as senator. Yet I wouldn't count on it. Besides the expectations that a vice president be "loyal" to the president, there is also the fact that (as Sandbrook notes) in OTL McCarthy was undoubtedly influenced by the fact that in 1965 he joined the Senate Foreign Relations Committee, and was exposed to the views of Senator Fulbright and the committee's dovish staff:
"It is quite probable that the very fact of being on the Foreign Relations Committee and exposed to the ideas of Fulbright and his staff was a crucial fact in the evolution of McCarthy's thinking, *without which he might have remained relatively quiet on Vietnam* [my emphasis--DT] From 1965 onward, in fact, the committee became the single most important forum in Congress for criticism of the Vietnam imbroglio, not least because it was the only committee in either house with a chairman who opposed the war..."
http://books.google.com/books?id=wMqSzTPXl7QC&pg=PA129
As for Humphrey, some support for the idea that if not for loyalty to LBJ, he might have been a dove on Vietnam can be found in his memorandum of February 15, 1965, where among other things he noted that "It is always hard to cut losses. But the Johnson administration is in a stronger position to do so now than any administration in this century. 1965 is the year of minimum political risk for the Johnson administration. Indeed, it is the first year when we can face the Vietnam problem without being preoccupied with the political repercussions from the Republican right. As indicated earlier, our political problems are likely to come from new and different sources (Democratic liberals, independents, labor) if we pursue an enlarged military policy very long." For the full text of this memorandum--which was quite prescient in several respects--see
http://books.google.com/books?id=YRTeKY1xcVUC&pg=PA323 (Of course to say that a Humphrey who stayed in the Senate might have been a dove does not necessarily mean he would challenge LBJ in 1968. Challenging an incumbent president in the primaries is a long-shot gamble and Humphrey may just not have had the temperament for it. Still, Humphrey was capable of taking risks--a lot of people thought he was running risks by trying to get a strong civil rights plank into the 1948 Democratic platform in the teeth of opposition from the party's leaders.)
So *if* LBJ had chosen McCarthy instrad of Humphrey as his running mate in 1964, the idea that 1968 might see a dovish Humphrey running against a hawkish McCarthy is not totally implausible. The question is whether it is really plausible that LBJ *would* have chosen McCarthy instead of Humphrey in 1964. LBJ toyed with the idea, but I don't think it's too likely he would have done so. For one thing, Robert Kennedy and his circle were dead set against the idea. If LBJ wasn't going to choose RFK, McCarthy as a Catholic "substitute" would be an insult. Kennedy's supporters much preferred Humphrey. (McCarthy made things worse by criticizing RFK's decision to run for the Senate from New York.) Also, of course, the unions preferred Humphrey, and he seemed more likely to help the party in the Midwest. McCarthy had southern support because he was less identified with civil rights than Humphrey--even James Eastland urged LBJ to pick McCarthy!--but LBJ was writing off the South or at least the Deep South, anyway. Also, Humphrey was really more LBJ's type as a politician than the poetry-writing, Aquinas-expounding McCarthy. Finally, the only member of LBJ's inner circle who really favored McCarthy was Walter Jenkins. So all in all, I don't think McCarthy had too much of a chance. But if he had been chosen, I don't see it implausible for him to end up much more hawkish than Humphrey.
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