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.”
