It's definitely a weird system. There's a primary election in Tucson in which each individual ward chooses the person who'll represent the relevant party (from that ward) at the general election. But then, in the general election, everyone in the city votes for one council member from each ward. To represent the entire city.
Judge Kozinski says that's unconstitutional. Judge Tallman says it's just fine.
Judge Kozinski writes the majority opinion.