The single member plurality voting system (SMP) is the most commonly used voting system in the United States. SMP works with geographically-defined "single member districts" that each send one representative to a legislature. Voters in a given district cast one vote for their favorite candidate, and the candidate receiving the most votes is elected. This system commonly works in a series of two elections, in which primaries are held to determine a nominee from each major party, followed by a general election that pits the primary winners against one another.
Of the 211 democratic nations of the world, 68 -- including the
United States and most other former British colonies -- use SMP as
their principal electoral system.
Of major, full-fledged democracies, however, very few use SMP.
Of the 45 nations with populations of more than 2 million recognized by
Freedom House as politically and socially "free", only eight use SMP.
Supporters of SMP tout the strong local representation afforded by single-member districts, as every representative represents and speaks for the people of a particular district. Furthermore, supporters argue, SMP tends to reinforce one-party government in a legislature and a two-party system, which they maintain leads toward greater accountability and more efficient government. Supporters also note that voters easily understand SMP.
Nevertheless, the majority of democracies have turned away from SMP because of the problems and injustices which can result from it. Common objections to SMP include:
- SMP tends to produce legislatures that, on the whole, do not represent the diversity of political opinion in the electorate. Certainly in any given level of election, only one representative can speak for all the people in a particular district.
- In racially diverse areas with a history of racially polarized voting, racial minorities will not gain representation unless districts are drawn to make them the majority in particular legislative districts – not always easy to do and inevitably controversial.
- Because of population shifts, districts must be redrawn periodically to avoid violation of the one person, one vote principle. This process of redistricting is very open to political manipulation, particularly given modern computer technology.
- SMP legislative and executive elections can be so distorted by "wasted votes" won by "spoilers" outside the two major parties that minority viewpoints can actually win power. A government has not come to power in the United Kingdom with more than 45% of the popular vote in decades, and some of those governments clearly won only because of split votes in the opposition. Legislatures elected by SMP thus can be unresponsive both to the will of the majority and the opinions of minorities.
- SMP has a history in countries like India and Canada of producing regional parties that have led to fragmentation of national parties. In Canada, the second and third largest parties (the Bloc Quebecois and the western-based Reform Party) in the parliament after the 1993 elections had not nominated candidates that faced one another in a single district election that year.
- Comfortable majorities for one party or one community of interest can make elections extremely non-competitive. More than 40% of state legislative races were not contested in the United States in 1998, while the average U.S. House race was won by a margin of more than 70% to 30%. Some state legislative chambers have not changed party control in more than a century.
- In part because of safe districts and in part because of the difficulty in mounting viable candidacies from across the spectrum, SMP tends to have lower voter turnout than other systems.
- In closely-contested races, there tend to be only two candidates, which creates incentives for very negative campaigning – candidates often use opinion polls and focus groups to fashion negative ads designed to drive voters away from their opponent.
- In competitive races, campaigns ignore the majority of people who are likely to vote because they already have decided on a candidate and instead focus on those relatively few "swing voters" who have not made a decision. These swing voters gain inordinate influence both in campaigns and between campaigns.
- Women are less likely to run and win than they are in multi-seat district elections.
in the United States of course has much to say for it,
despite these drawbacks. Some argue that these positive aspects are
less due to SMP than to other factors, including a strong and
independent judiciary, a free press, an active citizenry, federalism
and checks and balances within federal and state government. America
has a history of innovation and the courage to embrace reform where
necessary. As better alternatives to SMP become available, Americans
should seriously consider their benefits.