Our presidential primary is longer than any other industrialized country, and becomes expensive theatre rather than a good way to select a leader. Driven by advertising dollars, the media love it. The candidates have to raise even more from PACs and donors. By the time the election actually rolls around, the people are weary.
The presidential primaries seem to drag on a long time. With the current political climate, that allows the candidates and their respective parties time to air more attack ads and aggressively nasty campaigns. The candidates spend weeks attacking each other and then turn their rancor on the opposing party's candidate. Instead of creating an informed debate for voters to use in making their choices at the polls, the nastiness just festers and spreads.
The US primaries and general elections should be decided by Instant-Run Off voting, or Ranked Choice Voting, as opposed to the First Past the Post system we have. We need to ensure more parties and independent voices get into the US Congress and state governments, or else we're doomed to the destructive path we're going down.