Replace Plurality Elections
Problem: Many jurisdictions in the United States and other nations use plurality voting (sometimes misleadingly called "first past the post") where the candidate with the most votes is elected no matter how low that candidate's percentage of the vote. This system works fine when there are only two candidates in a race. When three or more candidates compete for a single winner office, however, the winning candidate can win with well under fifty percent of the vote. This means that a majority of voters may actually prefer the candidate who finished second. This violates commonsense democratic principles for fair elections of a single winner office, such as mayor or governor.
Solution: Under instant runoff voting, voters rank candidates in order of preference. If more than two candidates receive votes, the candidate with the fewest first choices is eliminated. Voters who ranked the eliminated candidate first now have their ballots counted for their second choice. This process continues until there are two candidates left and the one with the majority of votes is the winner. (The tally sometimes is shortened to to declare a winner as soon as one candidate earns a majority of continuing ballots, including a majority of first choices, as this candidate cannot be defeated.)
By ranking candidates, voters are able to express their true preferences without worrying about wasting their votes or spoiling the election and helping elect their least favorite candidate. For this reason, IRV often can lead to higher turnout and stronger democracy. Candidates need to build a base of first choice support, but also reach out to the broader voting population in order to be acceptable to the majority. Turnout is most clearly affected when IRV replaces two rounds of voting with one, as one of those rounds of voting typically will have lower turnout.