Does June equal November? Why California's open primary may tell us less than we think.

Did last night portend November in California? Likely not.

On Sunday, in a preview post looking at the newly established "top two" open primary in California, I posed three questions to ponder as we followed the results Tuesday night (and, as it happened, Wednesday morning). The second question was this one:

Will June be a predictor for November in key races?

At least one member of the pundit class, Aaron Blake of the Washington Post, seems to think so, if his post-mortem of last night's primary is any indicator:

The new primary system, combined with a citizen-drawn redistricting map, has put many of the state's incumbents into tough races.

Below, we tell you who is looking vulnerable, and who had a good night.

Blake then proceeds to identify several Democratic incumbents (and, to be fair, one Republican'Brian Bilbray of San Diego) that he declared as imperiled come November.

That, indeed, was one of the great temptations of having an open Congressional primary. With all candidates on one ballot, there was tremendous ease in drawing conclusions based on the raw vote from last night.

The problem with analysis such as this? It is almost certainly inaccurate, and by more than a degree or two.

Start with a simple fact'turnout yesterday was a fraction of what will show up in November. In 2008, 13.7 million Californians participated in the November general election. While yesterday's numbers will certainly climb as absentees and provisionals continue to get counted, it presently sits at a tick over four million voters. So drawing vast conclusions when less than a third of November voters showed up yesterday, seems a bit dangerous.

An election turnout is not like a public opinion poll'pollsters weight their numbers based on a perception of what the electorate will look like. Primary turnout is unweighted, and certainly tilted.

Consider: if one looks at the presidential turnout on Tuesday, the numbers are nowhere near what they'll be in November. 51 percent of the ballots yesterday at the presidential level were cast for President Obama, while 47 percent of the ballots were cast for all of the combined Republican candidates.

Does Blake, or anyone, expect Barack Obama to carry the state of California by four percent in November?

Given that the primary electorate appears considerably less Democratic than the general electorate will be in November, drawing sweeping conclusions on the House races, based on their results last night, would almost inevitably paint a picture that is far more optimistic for Republicans than the reality of the situation merits.

Sure, some of the incumbent Democrats who polled in the 40s will have to watch their backs in November. But to imply that they are somehow more vulnerable now than they were perceived to be before Tuesday may well be an act of pundit malpractice.