:Possibly the reasoning was, "Roosevelt invited the war in order to get reelected." It may happen with two-term US presidents, but they have only one chance.    

 == Vice president eligibility == 

 "A very popular president runs as the vice president during an election, but everyone knows they are really voting for him. After the election, the president resigns." This popular vice president who becomes president again would have the support of the people, in order to win votes, and maybe also the support of US Congress, but it would reasonably count as being reelected again. In fact, there are situations like the current president of Turkey that are very similar to this. (In his case, he couldn't become prime minister again.)