Like Instant Runoff, Approval Voting aims to identify the most widely-accepted candidate (which usually tends to be a centrist candidate). But approval voting may do an even better job.
In the 2008 primaries, with a dozen candidates in the race, Senator Joe Biden said he was "second on everyone's list". What if that was true? He would be the person most acceptable to everyone, but he would be the first person eliminated in a runoff, instant or otherwise, since he would have the fewest first-choice votes of any candidate.
Approval Voting is used to select the Security General of U.N. So it clearly works reasonably well. Maybe, just maybe, somebody learned something about how to make things work in the 200 years since the country was founded (the U.S. that is).
Maybe Instant Runoff makes more sense when you're selecting for a collection of council members, but approval voting may be a better strategy when choosing a single-winner position like president.
In 2000, Democrats could have voted their approval of both Ralph Nader and Al Gore. In 1992, Republicans could have voted their approval of both Ross Perot and George Bush. In each case, it can be positively argued that the race was won by the candidate who was least desirable to a majority of voters.)
For more on this subject, see:
- Approval Voting