Democratic superdelegates are free to support any candidate for the presidential nomination. This contrasts with pledged delegates who are selected based on the party primaries and caucuses in each U.S. state, in which voters choose among candidates for the party’s presidential nomination.

A caucus is a meeting of supporters or members of a specific political party or movement.

Caucus. A closed meeting of members of the same political party at the state level to vote in candidates for President and to select delegates to represent that state at the National Convention late in the summer.

Each party holds a national convention to select a final presidential nominee. State delegates from the primaries and caucuses selected to represent the people will now “endorse” their favorite candidates and the final presidential nominee from each party will be officially announced at the end of the conventions.

The formal purpose of such a convention is to select the party’s nominee for popular election as President, as well as to adopt a statement of party principles and goals known as the party platform and adopt the rules for the party’s activities, including the presidential nominating process for the next election cycle.

In the United States, a political convention usually refers to a presidential nominating convention, but it can also refer to state, county, or congressional district nominating conventions in which candidates are nominated, delegates to larger regional or national conventions are elected and the party platform is …

Some historians have suggested that two-party systems promote centrism and encourage political parties to find common positions which appeal to wide swaths of the electorate. It can lead to political stability which leads, in turn, to economic growth.