I once had a series in soc.history.what-if in which Young Bob defeats Joe McCarthy in 1946, and goes on to be Dewey's running mate in a successful 1948 campaign. So this makes him vice-president (and one Puerto Rican nationalist's bullet away from the presidency). Part 4 is of my series is a DBWI:
***
Probably very few people have heard of Joe McCarthy. Even experts in Wisconsin political history know only that he made two unsuccessful attempts at unseating Wisconsin GOP Senators in primaries (Alexander Wiley in 1944, Bob La Follette, Jr. in 1946), was appointed Senator by Governor Rennebohm in 1948 to fill the vacancy caused by La Follette being elected vice-president, and then lost to Democrat Thomas Fairchild in 1950, after which he faded into political obscurity. (Personally, although McCarthy was an undistinguished Senator, I don't think it is entirely fair to blame him for losing in 1950. That was just too much a Democratic year. No matter how President Dewey protested that Truman had really been responsible for the "loss" of China, the Soviet A-bomb, and the Korean War, the GOP, as the party controlling the White House, was bound to be blamed.)
But people forget that McCarthy gave "Young Bob" La Follette a run for his money in 1946. La Follette might have lost had he made the mistake he was tempted to make--endorse his old friend Ralph Immel against Governor Goodland. That would probably have driven thousands of Goodland supporters into McCarthy's camp. (So what if McCarthy had won the primary? In that event, he would probably have beaten the Democrat Howard McMurray in the general election, and would have served at least a full term in the Senate, but I still don't think he would have made any particular name for himself.) Anyway, I think the near-loss to McCarthy had two historically significant effects on La Follette:
(1) McCarthy had accused La Follette of being obsessed with helping labor and not interested enough in other groups, above all farmers. La Follette, realizing that this theme had come close to defeating him, hired a staffer who was very good at agricultural questions and who noticed an obscure provision of the Commodity Credit bill that the 80th Congress was set to pass at the end of its first session. This provision would have made it impossible for the federal government to build grain storage bins near farms. As the staffer pointed out to La Follette (who pointed it out to key GOP farm-state Senators, and especially to his friend Bob Taft) this would mean that if the fall of 1948 should bring a large harvest and a decline in farm prices--which in fact was to happen--the results could be politically catastrophic for the Republicans. With no bins available, farmers would not be able to deposit their grain and collect support payments--and Truman would be sure to blame "that notorious Republican 80th Congress." Fortunately, La Follette persuaded the other Republicans to delay this section's effect for a few years. Had the provision passed in its original form, I would by no means rule out a Truman victory in 1948, despite the Wallace and Thurmond candidacies.
(2) The failure of organized labor to back him against McCarthy, and the fact that the left-wing CIO unions were especially hostile, may have been behind his decision to form the "new La Follette Committee" to investigate communism. Oh, I'll grant the committee wasn't a *total* success. Communists and fellow travelers, for obvious reasons, accused it of "witch-hunting." Liberals, while conceding that La Follette was a lot fairer than Martin Dies or Parnell Thomas, argued that the committee didn't really discover much that was new. It did have a big effect on the GOP, though--it (and his denunciations of the Soviet Union) gave him a reputation as the party's "Mr. Anti-Communism" and caused a lot of the Republicans to lose their hostility to La Follette despite his still generally liberal record on domestic issues. The result is that there was not as much protest as one might expect on the Right when Dewey chose La Follette as his running mate. (Even so, "Young Bob" did have to move to the right a bit--announcing that he now supported Taft-Hartley, though he wanted "a few changes" in it.) Even the *Chicago Tribune*, while expressing unhappiness over another "me too ticket" in domestic affairs, admitted that "whatever our disagreements with Senator La Follette, he and his family have always stood for putting America First."
In retrospect, it is a good thing for the GOP that Dewey chose La Follette. The Republican victory was surprisingly close in Illinois, Ohio, Wisconsin, and California. No doubt Earl Warren (who was also mentioned as a possible vice-presidential candidate) would likewise have enabled Dewey to carry California, but I am not sure about the other three states. Even in OTL, the closeness of the election made the *Chicago Tribune*'s ludicrous "Dewey Defeats Truman In Landslide" early evening edition a collector's item...
https://groups.google.com/d/msg/soc.history.what-if/mRTOgEp6hEI/Ijpl0ZaB1fgJ
***
For Parts One, Two, and Three see
https://groups.google.com/d/msg/soc.history.what-if/E7W7oekwLyY/HsjkH40BQtgJ
https://groups.google.com/d/msg/soc.history.what-if/ER88zGXFw9k/CeP8cih4J8oJ
https://groups.google.com/d/msg/soc.history.what-if/6KOM7ElfQUY/uxxudWzhSoMJ