Nate Cohn: “The quirks that make the California primary risky for Democrats also make it a leading indicator of the general election. … Since 1990, the major party vote share in top-two congressional primaries in Washington (which also uses the top-two system) and California has differed from the general election result by an average of just three percentage points.”

“This is about as good as any data we’re going to get. The average House poll over the final three weeks of an election is off by an average margin of 6.2 points… So the primary results are a bit like getting a free round of more than 50 final House polls in early June.”

“If this is a wave environment like in 2006 or 2010, which would probably make the Democrats slight to modest favorites to retake the House, it shouldn’t be too hard to tell. Seat by seat, Democrats would probably be pretty close to half the vote in the seven California districts that Hillary Clinton won in Republican territory in 2016.”

David Wasserman: “Under California’s rules, all candidates in all 53 districts run on the same primary ballot and the top two finishers, regardless of party, advance to the general election. In a few GOP-held seats, there are so many Democrats running that they risk splitting enough votes to allow two Republicans — and zero Democrats—to advance to November. That would be a nightmare scenario for Democrats in otherwise terrific pickup opportunities.”

“Although a shutout isn’t especially likely in any district, it’s a legitimate fear for Democrats. Despite President Trump’s unpopularity in the state and the news that registered Republicans just fell behind ‘no party preference’ voters into third place on the state’s rolls, statistics on vote-by-mail ballots show Republicans, white voters and older voters returning primary ballots at significantly higher rates than Democrats, non-white voters and young voters.”

“Originally, Democrats’ greatest shutout fear was in California’s 48th CD, where GOP Rep. Dana Rohrabacher faces an intra-party challenge from former ally and Orange County GOP Chair Scott Baugh. But with several late polls showing Baugh falling back, some Democrats are more concerned about the 39th CD, where GOP Rep. Ed Royce is retiring and a GOP drive to recall state Sen. Josh Newman over his gas tax vote is priming GOP turnout.”