There are three types: 1. Closed Most states in the US have this. You vote for a nominee to be put on the ballot from your registered party. You cannot vote for a nominee from another party. 2. Open A fair amount of states have this kind of primary. Each person gets one vote for each position, but can choose the party they vote in, unlike closed primaries. 3. Blanket Only three states have this and its constitutionality has been debated. Basically, it goes further than an open primary: you can vote for whomever you want, regardless of party affiliation. (Best for third parties, but still...) Each has its cons: Closed: Difficult for third parties to enter. Open: (My favorite) There can be dilution of results: Take, for example: Obama is the incumbent, so Democratic voters get together to try and nominate a weak candidate for the Republicans. Blanket: Same as above, except with worse dilution Edit: I forgot to post a poll, but please give your opinion in the comments.
My heart says Open primary, just to cause electoral chaos with the other party (let's all vote Santorum!) But my brain says Closed. Parties should pick their candidates among themselves, and it's undemocratic if opposite party members and supporters interfere in this.
Closed, I feel like an open system would backfire on itself with Democrats picking the weakest Republican and vise versa.
Actually my APGAP teacher's brother switched parties so he could vote for the weakest Democratic candidate in '08
In the primary. It is when the party decides who it wants to run for offices. Anyone can vote for the president, but in most states only a member of a party can vote for who represents them. (What the Republican's are doing right now.)
It ensures cases like the one you mentioned don't happen. It ensures only those dedicated to the party can vote for the leader. It also includes some unelected positions like senators, party president, etc.