The trend towards Presidential caucuses and primaries developed fairly recently. Historically, only a few states used primaries and caucuses in the Presidential election procedure. Since the 1970s, the tendency towards more voter participation has meant that today all states hold a primary or caucus. States choose whether they want to conduct a primary or a caucus. In some states, both take place. Democrats in Kentucky, for example, hold a primary whereas Republicans conduct a caucus.
However, primaries do not select a Presidential candidate but rather delegates who are then “pledged” to vote for the candidate at the party's national convention. Candidates have to convince their party before they are nominated and put on the ballot. After each primary or caucus, candidates tend to drop out of the race when it becomes clear that they will not command enough support from their party to become presidential candidate. At the end, two candidates - one each from the Democrats and Republicans- is nominated as Presidential candidate and goes campaigning throughout the nation. Of course, other parties like the Greens or Libertarian Party are included in this procedure but have much lower chances against the two major parties in the Presidential election.
Open and closed primaries
Today primaries and caucuses are held from January to June in the Election year. Primaries are conducted and funded by state governments. The procedure is the same as any other election: voters go to the polling place and cast their vote. However, they can also be held as “closed” primaries, which means that only registered party members are allowed to vote. For example, only declared Republican Party members can cast their vote in the Republican primary. In open primaries, all eligible voters can participate even if they aren't affiliated to any political party. Other variations within primaries include the semi-closed primary, semi-open primary or the nonpartisan blanket primary.
See also: Caucus
, Presidential election
, Democratic Party
, Republican Party