I natt möts Sanders och Clinton själva öga mot öga

The series of presidential primary elections and caucuses held in each U.S. state and territory is part of the nominating process of United States presidential elections. This process was never included in the United States Constitution; it was created over time by the political parties. Some states only hold primary elections, some only hold caucuses, and others use a combination of both. These primaries and caucuses are staggered generally between January and June before the general election in November. The primary elections are run by state and local governments, while caucuses are private events that are directly run by the political parties themselves. A state's primary election or caucus is usually an indirect election: instead of voters directly selecting a particular person running for President, they determine how many delegates each party's national convention will receive from their respective state. These delegates then in turn select their party's presidential nominee. Each party determines how many delegates are allocated to each state. Along with those delegates chosen during the primaries and caucuses, state delegations to both the Democratic and Republican conventions also include "unpledged" delegates, usually current and former elected officeholders and party leaders, who can vote for whomever they want. This system of presidential primaries and caucuses is somewhat controversial because of its staggered nature. The major advantage is that candidates can concentrate their resources in each area of the country one at a time instead of campaigning in every state simultaneously. However, the overall results may not be representative of the U.S. electorate as a whole: voters in Iowa, New Hampshire and other small states which traditionally hold their primaries and caucuses first usually have a major impact on the races, while voters in California and other large states which traditionally hold their primaries last in June generally end up having no say because the races are usually over by then. As a result, more states vie for earlier primaries to claim a greater influence in the process.