The trend towards Presidential caucuses and primaries developed fairly recently. Historically, only a few states used primaries and caucuses in the US Presidential election procedure. Since the 1970s, the tendency towards more voter participation has increased to such an extent that today all states hold a primary or caucus. Each individual state is allowed to choose whether it wants to conduct a primary or a caucus - some states even do both. For example, Democrats in Kentucky hold a primary whereas Republicans conduct a caucus.
Caucuses do not directly select a Presidential candidate, but rather delegates who are then “pledged” to vote for a particular 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 drop out of the race because they were unable to get the approval and backing of their party. At the end two candidates, one each from the Democrats and Republicans, is nominated as Presidential candidate and goes campaigning throughout the nation in order to win the presidency. Minor parties like the Greens or Libertarian Party are included in this procedure but have little chance against the two major parties in the Presidential election.
Democratic and Republican caucuses
Today primaries and caucuses are held from January to June every election year. Caucuses are part of the primary election process but are organized by state party officials and not by the state government like regular primaries. In addition, caucuses are generally only open to party members. Caucuses are more like "political events" and demand a higher level of political engagement, time and participation than primaries. It's therefore little surprise that fewer voters take part in caucuses.
The election process is simple in Republican caucuses. Voters listen to candidates' speeches and sometimes have the chance to talk to them directly. Afterwards they cast their vote in a secret ballot.
The Democrats' election process differs strongly from the Republican caucus. All voters in attendance are counted before any voting begins. Voters are then asked to form groups corresponding to their preferred candidate, or stand in an "undecided" group. This process means voters are publicly displaying their preferences as opposed to the secret ballot used by Republicans. The number of people in each group is then counted and any candidate who doesn't have the support of at least 15% of voters in attendance is then eliminated from the contest. The "realignment" phase then begins in which undecided voters and voters of the removed candidates have the opportunity to either choose another candidate or leave the caucus. The counting/eliminating procedure then continues until only those candidates with over 15% of voters are left.
See also: Primary
, Presidential election process
, Brokered convention