Does the Primary Indicate Who Will Win the Election?
Primary elections are party-specific elections that are held at the state level to help select party candidates who will run in general elections at either the federal or state levels. Primaries are run and administered by the states, so the rules that govern them differ considerably from to state. Some state primaries are only for party members, while some states hold primaries that are open to all eligible voters. The primary does not decide who will win an election, but it usually indicates who is eligible to run in the general election.
1 Non-Presidential Offices
Candidates for offices other than President of the United States are usually decided in relatively direct democratic elections. That is, the people who live in the state or city cast direct votes to determine who will represent their party. These primaries have a direct role in determining the winner of a general election since they decide who the candidates will be. In other words, one of the primary winners must necessarily win the office at hand.
2 Presidential Primaries
Presidential primaries are not strictly examples in direct democracy as they are held in an indirect manner. That is, party delegates are chosen in each state, proportional to the state's population, and those delegates make the final decisions on candidates. So a highly populous state has more available delegates than one with a very small population. Delegates -- not primary voters -- make the final decision about who gets to represent their party in the general election.
3 How Delegates Work
Delegates almost always follow the will of the population they are representing. For example, when North Carolina's Democratic primary in 2008 resulted in the selection of Barack Obama to run for the Democratic Party, North Carolina Democratic delegates were expected to vote -- and did vote -- for Obama at the Democratic National Convention, where the final Democratic Party candidate was chosen. Delegate votes, not general population primary votes, indicate who gets to run in a general election for the party.
4 Indirect Democracy
Lay citizen primary voters may technically cast a majority vote in favor of one presidential party candidate who is rejected by state party delegates. This is unusual since state party delegates see their role as representing the will of their state party. Still, it is not prohibited for delegates to go against the state voters. Technically speaking, then, state presidential primaries do not even indicate who gets to run in a general election, much less who will win. Delegates themselves choose which party candidate may run -- and thus get a shot at winning -- the office of president.