We have two basic primary systems in this country, open and closed. In an open primary, any registered voter can vote for that party's candidate. In a closed primary, only a voter who registered as a member of that party can vote in its primary. (There are various kinds of restrictions, and they are enforced to varying degrees.) My state, Ohio, is closed. List of States with Open and Closed Primaries « Grassroots Idaho GOP The other factor that affects a primary is the sequence. The fact that New Hampshire and Iowa hold their primaries earlier than other states has given voters there a greater say in who the candidates are. This is a deceptive simple explanation, but might be enough to start a convo. No other democracy on Planet Earth uses the system we do here in the US. In your view, is our primary system good enough?