(Excluded from this analysis are races in which either the Democratic or Republican Party failed to run a single candidate, plus a few races in which both parties saw their percentages increase or decrease between the primary and general election.)
Indeed, of the 17 seats in which the net GOP vote rose between the primary and general elections, it did so by a mere average of 1.87 percent, while the average increase was 4.33 percent in the 66 seats in which Democrats made gains between the two elections. Only one seat swung more than 3.6 percent towards the GOP between the primary and general, whereas 29 districts saw gains of at least that amount for Democrats, and in seats that were far more competitive. Six of those races actually had massive Democratic gains into double-digit percentage points.
Turnout soars in California between primaries and general elections, as it does everywhere else. In 2000, over 10.4 million people voted in November after fewer than 7.9 million turned out for the primary. More than 12.3 million Californians voted in the 2008 general election, but fewer than 5 million turned out for the primary this June. The data points to one conclusion: A preponderance of the new general election voters each year favor Democrats, and that helps them improve margins from the primary.
Democrats have always had trouble turning out their voters for primaries in minority-heavy California, but they have flocked back to the fold in November. One such example occurred in the 1998 race for retiring Rep. Jane Harman's open seat, in which Steve Kuykendall fended off two credible GOP opponents in the jungle primary, while Janice Hahn had only nuisance opposition. On primary day, the five GOP candidates outpolled the two Democrats 61.2 percent to 33.9 percent, a result which might have indicated a strong GOP tilt to the seat.
And yet, in November, Kuykendall edged Hahn by a mere 48.9 percent to 46.6 percent; the net Democratic vote surged by nearly 12.7 percent between the primary and general elections. That same year, Rep. Loretta Sanchez (D), running her first re-election campaign, pulled in a meager 44.6 percent on primary day, while the GOP field (led by ex-Rep. Bob Dornan) netted 53.4 percent. But that fall, Sanchez crushed Dornan 56.4 percent to 39.3 percent, representing a 14.1 percent dropoff for the GOP.
Fast-forwarding back to 2012, Republicans note that Rep. Jerry McNerney's (D) 47.8 percent was slightly less than the 52.2 percent collected by his two Republican challengers in the 9th District, and that Rep. Lois Capps (D) garnered just 46.1 percent in the 24th District, versus 51.5 percent for two Republicans. Likewise, in the open 47th District, Democrats won 49.2 percent to Republicans' 50.8 percent, and in the open 41st District, the net Democratic vote was just 45.3 percent to 54.6 percent for Republicans. It's not that Republicans have no chance to win any of these seats this November, but the Democratic percentages here should probably be seen as floors that they are likely to build upon for the general, when turnout will surely increase. Based on the historical trend, it's quite possible that the net Democratic vote in each seat could bump up between 5 percent and 10 percent come November, enough to give Democrats a majority in each of these seats.
This is why Democrats should have been more prepared to head off a disastrous result in the 31st District. There, Gary Miller and Bob Dutton combined for 51.8 percent of the vote, winning the two runoff slots, while four Democrats -- one of them tabbed by the Democratic Congressional Campaign Committee as a marquee national candidate -- won the remaining 48.2 percent. Democrats and independents had crossed over to vote for Republicans in tight primaries in this region before.
In 1998, Miller defeated then-Rep. Jay Kim on primary day, when the combined GOP vote was 66.4 percent to just 27.7 percent for lone Democrat Eileen Ansari. But come November, there was more than a 13 percent swing in partisan preference, when Miller defeated Ansari 53.2 percent to 40.7 percent. Ansari made up that gap with an underfunded campaign, but she had much more ground to make up than Democrat Pete Aguilar would have had this year, given that the primary partisan vote was nearly even.
The good news outweighs the bad for Democrats, though. Democratic Reps. Jim Costa, John Garamendi, and Loretta Sanchez probably shouldn't panic. Yes, Costa only won 42.6 percent on primary day, and the net vote in his seat was just 52.2 percent for Democrats to 47.8 percent for Republicans. But this result is remarkably similar to what Costa's predecessor, Cal Dooley, pulled back in 1998. Dooley won an unimpressive 43.5 percent on primary day that year, while two GOP candidates netted 44.3 percent. But in November, Dooley thumped his GOP opponent 60.7 percent to 39.3 percent. Likewise, Garamendi outpolled four Republicans 52.2 percent-47.8 percent, this month, and is unlikely to do any worse on November 6th. The same could be said of Sanchez's 52.1 percent-43.9 percent over three Republicans.
The Thin Red Line
Conversely, Republican incumbents with mediocre primary performances are often in real trouble. Two such historical examples are James Rogan and Brian Bilbray, who saw their performances plummet from primary to general in two cycles. In 1998, Rogan saw his margins fall from a 59.1 percent to 36.7 percent Republican advantage in the primary to a narrow 50.7 percent to 46.4 percent win in November. In 2000, Rogan lost to Democrat Adam Schiff in both elections. (Primary: 48.8 percent to 47.3 percent; General: 52.7 percent to 43.9 percent.)
Some of that can be blamed on changing demographics and backlash to the Clinton impeachment, but followed the same two-cycle path to defeat. Bilbray won his 1998 primary handily over Democrat Christine Kehoe 52.9 percent to 40.8 percent, but that fall he edged her by only 48.8 percent-46.6 percent. In 2000, Bilbray again won the primary, this time by just 50.9 percent-45.8 percent over Susan Davis, but he lost to her a few months later, 49.7 percent-46.2 percent. History could repeat itself in 2012, given that Bilbray, who returned to Congress, pulled in a worrisome 41.0 percent in the 52nd District primary on June 5th. (The net GOP vote was 48.8 percent, versus 46.3 percent for Democrats.) Likewise, while Republican Rep. Dan Lungren's 52.7 percent primary win over Democrat Ami Bera's 41.0 percent may not be a squeaker, you can expect the fall results to be much closer, and if Lungren does survive this year, he'll undoubtedly continue to be targeted for the rest of the decade.
California Democrats have occasionally failed to do as well in November as they have in the primary. But those failures have been rare, marginal, and never enough to swing an election result. For instance, in 2000, Capps outpaced two Republicans in their primary 55.3 percent to 42.6 percent, but was held to a slightly narrower 53 percent to 44.4 percent win in November. That same year, then-Rep. Ellen Tauscher (D) notched a primary win of 54.4 percent to 43 percent over three Republicans, followed by a smaller November victory of 52.7 percent to 44.2 percent. Republicans surely hope they can do the same to certain California Democrats in 2012, but it's worth noting that Capps's and Tauscher's areas were a bit more ancestrally Republican back then, represented by Republicans in the House through 1996, with larger pools of GOP voters to drum out in November. Most of the other examples in this category involve Republicans in hyper-Democratic seats raising their low primary percentages to slightly less low general election performances.
Again, this is not to say Republicans are without hope in California's swing seats. Both 1998 and 2000 were good years for congressional Democrats nationally, and we don't know yet which way the wind will be blowing in 2012. Republicans can hold on to some hope that the primary results this year don't represent the high-water marks for their candidates. Still, the historical trend suggests that, when the small number of June primary voters is replaced by the larger pool of general election voters on November 6, the Golden's State GOP's margins have nowhere to go but down.
Scott Bland contributed