You’re telling me that who people vote for doesn’t really matter in regards to who gets elected‽‽‽ Here‽‽‽ In America‽‽‽
Yerp. Well, I believe the story goes like this. We used to have an open primary, back in the day. It was the awesomest primary system ever. Basically you got a combo ballot, where you could choose a Democrat for one office, a Republican for another, etc IN THE PRIMARY. You could end up with two Democrats running against each other in the general, or two Republicans (you still can, but it’s harder). Basically party was irrelevant. The two most popular candidates faced off against each other and people cared about the result, because it was, for example, two qualified Dems instead of one qualified Dem and some guy who got on the ballot because he paid the $50 filing fee and put an ® next to his name so he could catch all the protest votes. The best thing was there was no such thing as a safe seat–you could be in a 98% Dem district, be a five-term incumbent, and you’re pretty safe in the primary because primary turnout is never great, but you could still lose in the general election to the other Dem who came in a distant second in the primary.
Both parties HATED the open primary (see: party irrelevance), sued, and it was shitcanned. Then we had an initiative that restored something very much like the open primary, but technically meeting all the requirements from the lawsuit. The parties still hate it. So, the state Democratic party completely, and the Republican party partially, took their balls and went home. We’ll do our own thing, thanks, and now they do the caucus. But the primary was established by popular initiative, making it really hard to get rid of, so we have the dual system. The caucus is the “real” method for selecting candidates, and the primaries are euphemistically called the “beauty contest”. i.e. a measure of how much people like the candidates, but with no weight.
Not that there haven’t been attempts to get rid of it, but it’s hard. I forget if the Republicans still use the primaries for some percentage of the whole for one thing, which means it still has some minimal value for some people, but also people are super-shy of repealing initiatives here. Heck, it’s still popular here even though nobody uses it–most people in the state would likely support a constitutional amendment bringing back the open primary (those that remember it anyway) and prohibiting the caucuses – and if both parties said they would still refuse to accept the results, we’d say don’t let the door hit you on the way out, we’ll vote for the Freedom Socialists or somesuch until you come crawling back. We’re that kind of state, politically. Ornery.