Vox has a good article on the top two primary mess.
California's primary elections on June 5 will be one of the most consequential — and bizarre — contests of the entire primary season. The Golden State is crucial to Democrats’ effort to retake the House — Republicans currently hold a whopping seven districts Hillary Clinton won, and Democrats are eager to pry them away. The bizarreness, though, stems from California’s extremely unusual “top two” primary system — which pits all candidates of all parties against each other and lets only the first- and second-place finishers move on to the general election.
Often, the top two finishers are one Republican and one Democrat, setting up a normal partisan general election contest. But the top two can also be two candidates from the same party, which would lock in the partisan outcome of a race months in advance. This year, Democrats are anxious that they will end up shut out of several key House races where they have multiple candidates running — which could badly hurt their chances of retaking the chamber. Republicans, meanwhile, dread being locked out of the governor’s race, an open contest now that Gov. Jerry Brown is term-limited out. They fear that would depress their voters’ turnout this fall.
So naturally, both parties are furiously trying to game the system. Each is trying to make sure its votes are as concentrated as possible while the other party’s are divided. But those pesky candidates have minds of their own and often defy their own parties’ wishes. “It has the feeling of one of those civil wars in the Middle Ages, where the king is fighting against barons and there’s multiple alliances that form and collapse,” says Eric McGhee, a research fellow at the Public Policy Institute of California. “It’s a lot less straightforward than just you got your Democrat, you got your Republican. It’s sort of organized chaos.”
https://www.vox.com/2018/5/29/17381244/ ... -primariesBut there is a way the top-two system can go quite awry. Sometimes, in districts that are politically divided, two candidates from the same party can end up making it through the primary, due to unusual vote splits. Let’s say there’s a congressional primary where about 51 percent of the vote goes to Republicans and 49 percent to Democrats. One would think a Republican versus Democrat top-two matchup would best represent voters’ preferences in this swing district.
But think of the total primary vote as a pie. The candidates are all trying to get slices of that pie, and whoever gets the two biggest slices wins. How much of the pie each party gets doesn’t matter. So if that 51 percent for the GOP is split among two candidates and that 49 percent for Democrats is split among, say, four candidates — then the first- and second-place finishers could well be the two Republicans. This isn’t just hypothetical — it happened in California’s 31st District in 2012. The two Republicans got 26.7 percent and 24.8 percent of the vote. The top Democrat got 22.6 percent, with the rest of the vote (totaling 25.9 percent) being split among three other Democrats, so the party was shut out of the general election for the House in a district Barack Obama ended up winning handily.
CNN looks at key races.
https://www.cnn.com/2018/05/31/politics ... index.htmlCalifornia voters go to the polls Tuesday in the state's top-two primary, where the top two finishers will advance to the November ballot. But with so many candidates running in the most competitive races, there's a chance the vote will be splintered among the Democratic candidates -- creating a scenario where two Republicans could advance to the November ballot. Will Democratic enthusiasm be a blessing or a curse? We'll find out Tuesday night in these races: