Each election cycle, there are fears that third party candidates will “spoil” one of the major candidates’ victories due to the dominance of plurality voting. As a result, many localities in Democratic states use ranked choice voting (RCV), and several Republican-dominated Southern states have used runoff elections for decades. These systems can mitigate spoiler effects, but they fail to fully satisfy Independence of Irrelevant Alternatives (IIA). Many states have banned RCV due to the expensive process of counting its complex ballots, which also applies to cardinal voting systems. Even if voting machines were perfect and timely, Arrow’s Impossibility Theorem states that no voting system satisfying IIA also respects unanimous relative preferences of candidate A to candidate B.
But there exists a way to greatly reduce the spoiler effect without an expensive counting process. Approval voting, in which each voter simply casts one equally valued vote for every choice that satisfies them, does not require multiple rounds of counting or any mathematical operation more complex than addition. It may not always elect the candidate that voters would give the highest average rating, but it is probably the best option to ensure the fewest disgruntled voters and calm political polarization. Virtually no places use this system, however, despite its ease of implementability in casual social settings.
