Direct primary

A primary election is not an election. An election is a formal decision-making process by which a population chooses an individual to hold public office. A primary “nomination” narrows the field of candidates before a general election for office. Primary elections are the means by which the general public can indicate their preference for a candidate in an upcoming general election or by-election.

Primaries are common in the United States, where their origins are traced to the progressive movement to take the power of candidate nomination from party leaders to the people. Political parties control the method of nomination of candidates for office in the name of the party.

Other methods of selecting candidates include caucuses, conventions, and nomination meetings.

Where primary elections are organized by parties, not the administration, two types of primaries can generally be distinguished:

In the United States, other types can be differentiated:

The United States is one of few countries to select candidates through popular vote in a primary election system; most countries rely on party leaders to vote candidates, as was previously the case in the U.S. In modern politics, primary elections have been described as a significant vehicle for taking decision-making from political insiders to the voters, though this is disputed by select political science research. The selection of candidates for federal, state, and local general elections takes place in primary elections organized by the public administration for the general voting public to participate in for the purpose of nominating the respective parties' official candidates; state voters start the electoral process for governors and legislators through the primary process, as well as for many local officials from city councilors to county commissioners. The candidate who moves from the primary to be successful in the general election takes public office.

Primaries can be used in nonpartisan elections to reduce the set of candidates that go on to the general election (qualifying primary). (In the U.S., many city, county and school board elections are non-partisan.) Generally, if a candidate receives more than 50% of the vote in the primary, he or she is automatically elected, without having to run again in the general election. If no candidate receives a majority, twice as many candidates pass the primary as can win in the general election, so a single seat election primary would allow the top two primary candidates to participate in the general election following.

...
Wikipedia