16. The variety of runoff voting procedures
A system with traditional runoff elections in the event of no majority is clearly more democratic than the existing plurality rule, but suffers from drawbacks that instant runoff avoids.
There are two kinds of traditional runoffs.
A modern two-round runoff election, rather than just being a new election, eliminates candidates who are deemed to have little chance of winning. With the more common method, all but the top two candidates are eliminated. This expediency assures that the runoff will end with a majority winner on the next ballot. We can term this "batch elimination." Runoffs are most common in southern states and some municipal elections.
The other method involves dropping the bottom candidates one at a time in a series of runoffs. If no candidate has a majority, the bottom vote-getter is eliminated and balloting is repeated. Subsequent bottom vote-getters are removed until someone gets a majority. This procedure is used to elect party leaders in the U.S. House of Representatives. This is a time-consuming, though probably the "fairest," procedure since, in a crowded field, it allows for the possibility that a third place candidate may actually be more popular with a majority of the voters than either of the first two candidates, depending on the nature of the vote split.
"Batch elimination," while less democratic, is more practical for general elections since it is unreasonable to call voters back multiple times if there happen to be many candidates. Instant Runoff Voting, however, does not face the problem of turning voters out for a re-vote, and thus is free to use the more democratic sequential elimination of bottom candidates. This is how it is utilized in Australia.