Sometimes a party which is in the minority in the state may seek a more open primary system in order to attract more support. Finally, one of the main arguments for more open primaries is the contention that the candidates selected will have to appeal more to moderate, centrist voters, and thus are more likely to be moderates. I discuss whether this is true in my answer to Doug Arnold below . Compared to their countries, it may seem that the U.S. has no party system at all. Certainly, parties in the U.S. are relatively much weaker.
Money is a substitute for volunteer labor.
In a strong party system, party volunteers do the work that today paid persons do in American politics. The weaker the party system, the greater the need for campaign funds not only for labor, but for media time. Without strong political organization, candidates must necessarily place greater reliance on mass media. Both have the effect not only of weakening the power of parties, but also of shifting more influence over state-wide and national elections to the media. In fact, the U.S. Constitution takes a different approach and already creates more effective limits on the power of parties.