There are not just six parties, at the same time as there are really only two parties. Only two parties can be viable at the same time if the kinds of election are simple plurality voting (first past the post) combined with party control of candidate selection. If you change how candidates get on the general election ballot so parties don’t control that process (jungle primaries) more parties will appear to vie for the two general election spots. Until that time, there will only be two parties. One party is the Republicans and their wholehearted endorsement of authoritarianism. The other one is the Democratic party and their coalition of groups that make up anyone who isn’t white and male. Or as I put it previously,
If you want to make a change in US politics you have to join one of the two major parties, no matter which near-infinite flavor variation you put on your personal political views.
