It's very common to see a question that has a fair to decent answer with a very large numer of upvotes, followed by a better answer with half the upvotes.
Usually, it's because the higher ranked answer was posted first, and gets more upvotes due to its higher visibility as the first answer, or (in the short term) because early readers don't often come back to vote on the later answers.
Is it appropriate to help the best answer rise to the top by down-voting the overly-popular answer currently listed as the best, to counter the stream of +1s that it gets from being in that first position?