Voting Systems and Instant Runoff

     In my post on Presidential elections, I mentioned that even if the U.S. moved to a direct election system, it would still have some problems due to the plurality voting system.  The reason is that of the"spoiler effect," the tendency for two candidates with similar views to split the votes between them, allowing another candidate to win by virtue of the existence of a third party.  Examples of this that are often given are the 1912 election where the Republican incumbent W. H. Taft was challenged by Progressive Republican (Bull Moose) Theodore Roosevelt and Democrat Woodrow Wilson.  The two Republicans split the Republican vote, allowing Wilson to win.  A more recent, and more infamous, example is the 2000 Bush v Gore election, where Nader drew more liberals than conservatives and was one of the factors in Bush's win.  Although Gore still received a plurality in the popular vote, the spoiler effect in general is likely be a problem in the future.
     One solution to this problem is the instant runoff, also called the alternative vote or ranked-choice vote.  This system allows a voter to indicate their first choice, second choice and so on. When the ballots are counted the candidates with the least votes are eliminated and the votes re-assigned to the candidate ranked next on the ballot, until one candidate has a majority.
     There are many methods for choosing candidates for a large body by proportional representation, including Single Transferable Vote, a variation of IRV.  However, there are not so many for choosing a single official (like the president or a governor).  The other option would be a second round election, either by the people or legislature.  This is an improvement over current first past the post systems, but relies on the existence of a dominant two-party system.  When such a system begins to break down, as it did in the last French election, it can end up elevating candidates who do not have the support of the majority.  Therefore, the instant runoff seems the best system to use for executive offices.