Answer:
Political parties
Step-by-step explanation:
political parties developed the national convention to nominate presidential candidates. the main purpose of political parties is to nominate candidates that will stand for election weather at federal, state or local government levels.
A political party is an organization of people who share the same political ideology or same political positions they also field candidates for election into several government elective positions, once a political member selected by the party is Elected into Government the party implements its Agenda through this candidates.
The American political party system is divide into two namely republicans and democrats.