A common misconception about the primary election process is that votes are cast directly for candidates. In reality, they are cast in favor of delegates who will represent the candidates at the national conventions where they vote to select the party's presidential nominee.

The primary process was born from the desire of national and state parties to generate voter participation and grassroots mobilization. Traditionally, delegates who chose the presidential candidates were themselves chosen by caucus -- more informal town hall meetings.

Primary elections were first held in a limited number of states in 1912, but did not really take hold until the latter half of the century. Reforms during the 1968 and 1972 Democratic national conventions encouraged the proliferation of primaries, and by the 2004 elections over 40 states will be holding primaries.

Party delegates are allocated to each state according to population size. Since the population is always shifting, so is the number of delegates assigned to particular states. The Democratic National Convention plans on having 4,317 total delegate votes for the 2004 primary. The Republican National Convention will include 2,512 delegate votes.

In the Democratic primaries, delegates are won on a state-by-state basis and are awarded proportionally by the number of votes the candidates receive. For example, if a state has 50 delegates and Candidate X gets 60 percent of the votes in that state primary, then Candidate X will receive 30 delegates.

While some Republican state parties also use this form of proportional representation, others use a winner-take-all approach, or some combination of the two methods.

This election cycle, the Republican primaries are expected to be a formality, leading to the nomination of President Bush for reelection at the party convention in late August 2004. The last incumbent to compete in his party's primaries -- President Clinton in 1996 -- also ran unopposed and captured every delegate.

In the 1980 primaries, President Carter faced a determined rival in Sen. Ted Kennedy of Massachusetts, but went on to beat him by a 2-1 margin. In fact, the only sitting president to ever lose his party's nomination race was Franklin Pierce in 1856.

A key aspect of the primary system is that the elections are not held on the same day (like the general election) but are staggered over a period of months, from January to June. As the convention date approaches, the public generally gravitates toward the front-runners who have proven to be strong candidates. Usually, once the nomination is out of reach, opponents will drop out rather than waste money or political capital on a lost cause.

One result of this staggered schedule is that states with early primaries are extremely important to the candidates. A politician who does well early on is seen as a sure bet to supporters and potential campaign donors, while those who do not do as well will typically see their support wither and their funds evaporate.

New Hampshire and Iowa use this to their advantage. New Hampshire law dictates the primary must be held a week before any other primary, and Iowa law states the Iowa caucus must be held eight days before the New Hampshire primary. First-in-the-nation status carries benefits.

"It means more pork spending," said Andy Smith, director of the University of New Hampshire Survey Center. "New Hampshire is ranked 8th in the country in earmarked spending. There are a lot of politicians in the House and Senate with presidential aspirations who want to make friends with New Hampshire."

In a bid to counteract the disproportional influence of northern New Hampshire and Iowa, several Southern states banded together in 1988 to hold their primaries on the second Tuesday in March. This date came to be known as "Super Tuesday."

Other states eventually caught on to the Super Tuesday strategy, scheduling their primaries in groups. In some election years, this creates several Super Tuesdays. Due to the sheer number of delegates, these key primary dates have earned the reputation of making or breaking a candidate.

In the 2000 election, former New Jersey Sen. Bill Bradley conceded the Democratic nomination to former Vice President Al Gore shortly after a crushing 16-state defeat on Super Tuesday. Arizona Sen. John McCain fared only slightly better, managing to win a few northern states but losing the delegate-rich California, New York and Ohio in one blow to future President Bush.

This "front loading" -- the phenomenon of states holding their primaries in large groupings so early in the year -- has been criticized heavily as undermining the purpose of the primaries.

Some argue that because front loading dramatically shortens the primary election calendar, it restricts candidates from spending much time on campaigning and instead emphasizes big money fund raising and media blitzes.

"Candidates aren't going to have a chance to effectively campaign," said Smith. "They make a cursory, shallow visit to the state. It's a television-tarmac campaign where they fly into the airport and then leave."

The current 2004 primary calendar indicates there will be several Super Tuesdays -- this time starting in February, in addition to the customary first and second Tuesdays in March.

-- By Chris Nammour, Online NewsHour