Who chooses the delegates?
Delegates to the ‘national’ conventions are selected at the ‘state’ level by each political party’s ‘state committee’. which can be different from state to state..and even yearly.... also methods of convention delegate allocation differs from state-to-state and CAN BE CHANGED BY PARTY LEADERSHIP.... and be perfectly legal to do so.
Caucuses also come into play and open to all registered voters of the party at which delegates to the party’s national convention are selected....... the ‘voters’ in attendance divide themselves into groups according to the candidate they support..... The undecided voters congregate into their own group and prepare to be “courted” by supporters of other candidates... And thus it goes.... At the end of the caucus, party organizers count the voters in each candidate’s group and calculate how many delegates to the county convention each candidate has won.
Delegates can state support for a candidate or declare themselves to be uncommitted....again depending on the state because in some states, delegates are bound, or “pledged” to vote for the primary ‘winner’ in voting at the national convention.... In other states ‘some or all’ delegates are “unpledged,” and free to vote for any candidate they wish at the convention.