In the American electoral system, a primary election is an election that determines the nominee for each political party, who then competes for the office in the general election. A presidential primary is a state election that picks the delegates committed to nominate particular candidates for president of the United States. A presidential caucus, as in Iowa, requires voters to meet together for several hours in face-to-face meetings that select county delegates, who eventually pick the delegates to the national convention. No other country uses primaries; they choose their candidates in party conventions.
Primaries were introduced in the Progressive Era in the early 20th century to weaken the power of bosses and make the system more democratic. In presidential elections, they became important starting in 1952, when the first-in-the-nation New Hampshire Primary helped give Dwight D. Eisenhower the Republican nomination, and knocked Harry S. Truman out of the Democratic race because of his poor showing. In 1964, Lyndon B. Johnson ended his reelection campaign after doing poorly in New Hampshire.
After 1968, both parties changed their rules to emphasize presidential primaries, although some states still use the caucus system.
In recent decades, New Hampshire holds the first primary a few days after Iowa holds the first caucus. That gives these two states enormous leverage, as the candidates and the media focus there. New Hampshire and Iowa receive about half of all the media attention given all primaries.
The primary allows voters to choose between different candidates of the some political parties, perhaps representing different wings of the party. For example, a Republican primary may choose between a range of candidates from moderate to conservative. Gallup's 2008 polling data indicated a trend in primary elections towards more conservative candidates, despite the more liberal result in the general election.
In recent years the primary seasons has come earlier and earlier, as states move up to earlier dates in the hope it will give them more leverage. For example, Barry Goldwater won the 1964 nomination because he won the last primary in California. The logic is faulty--in highly contested races the later primaries have more leverage. Thus in 2008 California gave up its traditional last-in-the-nation role and joined 20 other states on Super Tuesday. Neither the candidates not the voters paid it much attention. Michigan and Florida moved up their primaries in defiance of national Democratic Party rules and were penalized. The result is the primary season is extended, and is far more expensive, and no state gets an advantage--except for Iowa and New Hampshire, which now have dates in early January.
In late 2009 the two national parties are meeting to find a common solution.
- Duncan, Dayton. Grass roots: one year in the life of the New Hampshire presidential primary (1991) 436 pages; on 1988 campaign
- Johnson, Haynes, and Dan Balz. The Battle for America 2008: The Story of an Extraordinary Election (2009), excellent history of 2008 primaries
- Kamarck, Elaine C. Primary Politics: How Presidential Candidates Have Shaped the Modern Nominating System (2009) excerpt and text search