That's not the case anymore; it was changed via ballot proposition several years ago, and now the top two vote-getters face off, regardless of party. That's why

That's not the case anymore; it was changed via ballot proposition several years ago, and now the top two vote-getters face off, regardless of party. That's why last year's big David Campos vs David Chiu battle happened twice: once on primary day (registered Democrats only, and just for practice), and then once again on Election Day (all voters, and this time it counts).