Strangely, I can't find much either way. I thought there was a clear case for Bush over Clinton absent Perot, but I may well be wrong.

I also worded the original comment too strongly. Clearly, charisma is a big factor in modern elections, and one data point isn't enough to disprove anything in any case. Concluding that "it's charisma, stupid" does seem to rely on very small-number statistics, though.