(The following article is taken from the U.S. Department of State publication, USA Elections in Brief.)
System for choosing party candidates has evolved over U.S. history
Rules within parties for nominating presidential candidates are not spelled out in the U.S. Constitution. As noted, there were no political parties in existence at the time the Constitution was drafted and ratified in the late 1700s, and the founders of the Republic had no interest in proscribing procedures for such entities.
Beginning in 1796, members of the U.S. Congress who identified with one of the political parties of the time met informally to agree on their party's presidential and vice presidential nominees. Known as "King Caucus," this system for selecting party candidates continued for almost 30 years. It broke down in 1824, a victim of the decentralization of power in politics that accompanied the westward expansion of the United States.
Eventually, the national nominating conventions replaced King Caucus as the means for selecting party nominees. In 1831, a minor party, the Anti-Masons, met in a saloon in the city of Baltimore, Maryland, to choose candidates and write a platform on which they would run. The next year, the Democrats met in the same saloon to select their nominees. Since then, the major parties and most minor parties have held national nominating conventions, attended by state delegates, to choose their presidential and vice presidential candidates and to agree on policy positions.
Advent of Television
Throughout the 19th and into the 20th century, the presidential nominating conventions, though attended by many of the party faithful, were controlled by state party leaders. These political "bosses" had used their influence to hand-pick their state's convention delegates — and to make sure that they voted "correctly" at the national party convention. Opponents to the party leaders demanded reforms to permit ordinary voters to select convention delegates. Primary elections came into being to do just this. By 1916, more than half the states held presidential primaries.
The movement was short-lived, however. Following the end of World War I, party leaders, who knew the primaries were a threat to their power, persuaded state legislatures to abolish them on the grounds that they were expensive and that relatively few people participated in them. By 1936, only a dozen states continued to hold presidential primaries.
But democratizing pressures reemerged after World War II. For the first time, television provided a medium through which people could now see, as well as hear, the political campaigns in their own living rooms. Plausible candidates for the presidency could use television exposure to demonstrate their popular appeal. The decades that followed brought back democratizing reforms to widen participation in party nominating conventions.
As a result, most states now hold primary elections. Depending on the laws of the state, primary voters may cast a ballot for a party's presidential nominee and a slate of "pledged" delegates, may vote for the presidential candidate with delegates to be chosen later to reflect the vote, or may indirectly vote for a candidate in a caucus by choosing convention delegates who are "pledged" to one or another nominee. Under the caucus system, partisans who live within a relatively small geographic area — a local precinct — get together and vote for delegates who are pledged to support specific candidates for president. Those delegates, in turn, represent their precinct at a county convention, which chooses delegates to attend the congressional district and state conventions. The delegates to these conventions ultimately elect delegates to represent the state at the national convention. Although this system takes place over several months, the candidate preferences are essentially determined in the first round of voting.The actual size of any state's delegation to the national nominating convention is calculated on the basis of a formula established by each party that includes such considerations as the state's population, its past support for the party's national candidates, and the number of elected officials and party leaders currently serving in public office from that state. The allocation formula that the Democrats use results in national conventions that have about twice as many delegates as those of the Republicans.
As a result of these reforming tendencies since World War II, two important trends stand out. First, more states have moved their presidential primaries and caucuses earlier on the calendar toward the decisive early stage of the nominating season, a trend known as "front-loading." Being an early primary or caucus state may allow voters in the state to exercise more influence over the ultimate selection of the nominees. In addition, it may encourage the candidates to address the needs and interests of the state early on, and may force candidates to organize within the state, spending money on staff, media, and hotels in order to try to obtain a decisive psychological victory early in the party nomination process.
In addition, in some parts of the country, states have cooperated with one another to organize "regional primaries" by holding their primaries and caucuses on the same date to maximize the influence of a region.
Both of these trends have forced candidates to begin their campaigns earlier to gain a foothold in the increasing number of states that hold the early contests. Candidates also have had to depend increasingly on the mass media — radio, television, and the Internet — and on the endorsements of state party leaders to help them reach voters in the multiple states that may be conducting their primaries on the same day.
Decline of the Political Convention
One consequence of the changes in the presidential nomination process has been the decreasing importance of the party's climactic, televised, national nominating convention. Today, the presidential nominee is effectively determined by the voters relatively early in the primary elections process. That eventual nominee may, in turn, even indicate his choice for a vice presidential candidate before the convention meets. (Vice presidential candidates do not run independently for that office in primaries but are selected by the party's winning presidential nominee.)
Thus, the presidential nominating process continues to evolve. In recent decades, this evolution has enhanced participation, improved demographic representation, and strengthened the tie between the average partisan and the candidates. As presently constituted, the process provides an advantage to candidates who are better known, can raise more money, have the most effective campaign organizations, and can generate the most enthusiasm among voters early in the presidential primary season.
The Internet Connection
Candidates and their supporters have been quick to adopt the Internet as a campaign tool. It has proved to be an effective and efficient way to solicit funds from potential supporters and to promote one's policies and experience. Campaign organizations now maintain their own blogs. The bloggers on these sites are campaign staffers paid to write about the statements and activities of their particular candidates. Meanwhile, thousands of independent bloggers write commentaries in support of their favorite candidates and engage in debate with other bloggers who oppose them.
Video sharing on sites such as YouTube has provided opportunities and pitfalls for political campaigning. Candidates have taken advantage of the technology to produce videos about themselves, occasionally humorous. At other times, candidates have been recorded in an unguarded moment saying or doing something that they would not say or do before a general audience — and having their faux pas shown countless times on the Internet and on television.