Political parties decide the number of delegates who will attend national
conventions, which has
grown consistently over
the years (see Figure 2).
Democrats use a formula known as the ‘allocation factor’, based on the number of votes each state awarded the Democratic candidate in the previous three
presidential elections, and the allocation of electors per state. Republicans use a simpler system, with each state assigned ten delegates, plus three per congressional district. In addition, the party also allocates bonus delegates to states and territories meeting certain criteria. Moreover, both national conventions include automatic delegates such as current and/or former elected office-holders and party leaders.