• In a presidential election year, primary elections are contests to determine who will represent each of the two major political parties in the fall's general election. While third parties can nominate candidates for the general election without primary elections, no one in recent history has won the presidency without first winning his party's nomination through primary elections. The rules for how presidential primaries work can be confusing, but the basics of the process are actually quite simple.
  
  

Registration and Eligibility

• Anyone who has reached her 18th birthday by the date of the primary election is allowed to vote, but she may take part in the election only if she has made herself eligible by registering in time, according to the Government Printing Office website.
  
  Election rules vary by state, but most require a form to be filled out and either dropped off at the election offices, mailed in or submitted online. Some states allow same-day registration for primary elections, while others require you to have your registration forms submitted up to 30 days before an election.
  
  

The Delegates

• A general election is a direct-results election in which voters cast a ballot for a candidate. But in a primary the voters are not voting for a candidate at all---at least not directly. The votes are to elect delegates who will go to the party's national convention. Once at the conventions, these delegates will cast their own votes to choose the party's presidential ticket in the general election, according to the Council on Foreign Relations website.
  
  Democratic primaries award delegates to candidates on a proportional basis. So one state's delegation may hold votes for several candidates. Republican primaries work the same way in some states, but others are "winner take all," where a simple majority of primary votes awards all the state's delegates to a single winner.
  
  Delegates pledge to vote for their candidate at the convention but are not legally bound to do so, according to the Time website.
  
  

Superdelegates

• The superdelegate is specific to the Democratic National Convention. The Republican Party does not have superdelegates.
  
  Within the DNC, there are certain delegates that are considered vital to the direction of the party. These special "superdelegates" are typically elected officials from Congress, party officials and other major players. At the convention, these delegates are not required to vote any particular way. They make up their own minds and vote for any candidate they choose. The superdelegates make up 20 percent of the delegates at the DNC, according to the Council on Foreign Relations website.
  
  

Open and Closed Primaries

• Primaries vary from state to state, but they are generally one of two main types---open or closed.
  
  The open primary is much like a general election format. The voters come to the polling place and cast their votes for whomever they choose regardless of party affiliation. Independent voters have a significant impact in open primaries. Voters may participate in either party's open primary, but may not cast ballots in both.
  
  In closed primaries the voters are usually required to be registered Democrats or Republicans in order to take part in the process. They also must take part only in their own party's selection process.
  
  

Caucuses

• A caucus is much like a primary in some places and consists of voters showing up and filling out a ballot in support of one candidate, with the majority vote-getter claiming victory. But in some states in the past, a caucus was a selection made by party officials behind closed doors with limited input from the public. The state party appoints delegates for the convention based on the outcome of the caucus. Caucuses, unlike state-run primaries, are sponsored by the parties themselves.