Is instant runoff voting a good idea?

The problem with having the winner of an election being the person with the most votes is that it discourages people from voting for third party candidates. People feel that voting for a third party candidate is wasting their vote, since the candidate has no chance of winning. Another problem is that a third party candidate can act as a spoiler in a close election, siphoning the votes from one candidate, who would otherwise have the most votes.

Instant runoff voting addresses that problem. The idea is to approximate having a runoff vote among leading candidates in the case that no candidate got a majority of votes cast. See Instant runoff example to see how it works.

Instant runoff is used in Australia and I would be interested in the views of any Aussie voters here. It is also used in San Francisco local elections. It could be implemented in the U.S. in national elections without any federal legislation. Each state is allowed to choose how it votes for senators and congressmen and states can also choose how they distribute their electoral votes in a presidential contest.

I think it is a good idea, but I am not sure. Suppose we used it just for presidential elections and a third party candidate got elected. That would be awful, because the president would have zero support in Congress. If we used it for both congressional and presidential elections then there would be the possibility of having the mess of many candidates from different parties. This may not be so bad, and I am not sure how likely that this would be.

In the U.S. there is also the problem of adding complexity to a vote counting process that already has problems, but I do not see this as an insurmountable obstacle.