Historically, Americans have been innovators in the design of electoral systems. In its day, the Electoral College was an impressive innovation. Several vote counting methods, including Cumulative Voting, Bucklin Voting and Coombs' Method, and Instant Runoff Voting originated in the United States. Today, the U.S. is less innovative nationally, but there is much diversity in the electoral systems used in state and local jurisdictions.
The map below was created by Sightline Institute and FairVote. Click the icon in the top left to open the map legend.
Plurality voting, used to elect the U.S. House Representatives as well as many state and local legislatures, is the most common and best-known voting method currently in use in America. Under plurality voting, an area is divided into a number of geographically defined voting districts, each represented by a single elected official. Voters cast a single vote for their district’s representative, with the highest total vote-getter winning election, even if he or she has received less than half of the vote. It is a winner-take-all method for electing the legislature, meaning that each district is represented solely by the party which earned the most votes in the most recent election.
There are several key weaknesses with plurality voting.
First, the shape of districts can have a huge effect on who is likely to win election. 51% of the votes earns 100% of representation, meaning small changes to district boundaries can have large impacts. As a result, gerrymandering to protect incumbents or weaken political opponents is common practice under plurality rules. This is a problem inherent in any single-winner system.
Second, plurality elections are prone to the vote splitting. In elections with more than two candidates, a candidate can get elected to a top executive office over the strong opposition of most voters because majority-preferred candidates can split their base of support between multiple similar candidates.
Vulnerability to vote splitting leads to a further problem. In order to prevent vote splitting from negatively impacting their chances, political parties will limit the number of candidates running. This in turn leaves voters with fewer choices.
Learn more about the ways RCV solves these issues here: Benefits of Ranked Choice Voting
While single-winner districts are used in most American legislative elections, a number of state legislative chambers and a majority of municipalities use some form of multi-winner districts. These jurisdictions include:
Historically, multi-winner districts were used to elect members of the U.S. House of Representatives and to elect most state legislators. Dan Eckam has created an infographic showing the use of multi-winner districts to elect each congress.
Winner-take-all is the norm in American jurisdictions, and is currently used for all national and state elections. However, proportional representation voting has been used to elect public officials in the United States since the nineteenth century. As shown on the map above, numerous cities used proportional representation in the 20th century, including including Cincinnati OH, Boulder CO, and New York NY. At the state level, Illinois used multi-member districts and cumulative voting, a semi-proportional method, to elect their House of Representatives for over one hundred years. Learn more of this history at Fair Representation Voting in the United States.
Currently, voters use proportional ranked choice voting, cumulative voting or limited voting in over two hundred United States jurisdictions to achieve proportional representation in their communities. Learn more at Jurisdictions Using Fair Representation Voting.