A short history of the Democratic Party Superdelegates from the washingtonpost.com

Superdelegates were first established by the Democratic Party in 1984, in order to give senior party leaders a larger voice in the nominating process. The creation of super delegates was largely seen as a reaction to the growing influence of rank-and-file voters and grassroots activists who party leaders believed had exerted too much control over the nominating process starting in the 1970s. While the Republican Party does not have superdelegates, the party does grant delegate status to a relatively small number of party committee members.