The Golden State wasn't always such a congressional battleground.
There were upsets, like when Democrat Adam Schiff unseated Republican Rep. Jim Rogan in 2000; or six years later when Democrat Jerry McNerney took out GOP Rep. Richard Pombo. But incumbents overwhelmingly won re-election.
That changed somewhat two years ago thanks in large part to the independent citizens panel charged with redrawing political boundaries. Democrats Ami Bera of Elk Grove, Raul Ruiz of Palm Desert and Scott Peters of San Diego all beat out incumbents.
Now, virtually all of them are top GOP targets in November, as well as first-term Rep. Julia Brownley, D-Westlake Village. The primary election will determine which Republican opponents the freshmen draw. Tuesday's drama is also heightened by a handful of intraparty contests. Under the state's elections system, the top-two candidates regardless of party qualify for the general.
Here's a look at seven of the races we're poring over from Sacramento.
Congressional District 4
Who we're watching: Rep. Tom McClintock, R-Elk Grove, Republican Art Moore and Jeffrey Gerlach, who declines to state a party.
Why we're watching: McClintock could get a general election scare if Moore, a businessman and military veteran, squeezes into the top-two on Tuesday. Perhaps that's why McClintock, a veteran of state politics and hero of conservatives, sent out mailers to Democrats that highlight Gerlach's "liberal" positions and never mention Moore. Two things to watch: Has Moore, a political newcomer with deep roots in the district, done enough to boost his familiarity with voters? Or, do Moore and McClintock split the GOP vote, with Gerlach getting requisite support from independents and Democrats? If Moore gets through, he'll have to step up his fundraising to sell himself as a viable alternative to McClintock in the foothills-based district.
Congressional District 7
Who we're watching: Republicans Doug Ose, Igor Birman and Elizabeth Emken.
Why we're watching: Seeking a return to Congress, Ose spent much of the primary criticizing Democratic Rep. Ami Bera. At the same time, he fielded persistent attacks from his right from Birman, on leave as the chief of staff to McClintock. Emken, an autism activist in her third run for federal office, took a slow-and-steady approach that largely avoided both paid and earned media. While Ose has doubled Birman's fundraising haul, the wild card was played in the last two weeks of the primary, when the Democrat-allied House Majority PAC saturated mailboxes and the airwaves with more than $200,000 worth of attacks against Ose. He's pushed back hard, saying the critiques are evidence that Democrats see him as the biggest threat. The deep-pocketed land developer not only has the resources to self-finance his campaign, but compared with his GOP opponents, he also can claim a more moderate record come the fall.
Congressional District 17
Who we're watching: Democratic Rep. Mike Honda, Democrat Ro Khanna and Republican Vanila Singh.
Why we're watching: The new "jungle primary" system has elevated this race to among the state's most intriguing – in more ways than one. First, there's the very real prospect that Khanna will advance to a fall rematch with Honda, a seven-term incumbent and favorite of Democratic allies in organized labor. Meantime, there have been allegations of underhanded tactics. Singh, a professor and doctor at Stanford University, contends a lesser-known Republican entered the race purely to boost the prospects of Khanna, a former deputy assistant secretary in the Commerce Department. Recently, reports surfaced that a labor-backed super PAC is spending money on behalf of Honda and Singh. Look for the Honda- Khanna Silicon Valley slugfest to extend through the summer.
Congressional District 25
Who we're watching: Republicans Tony Strickland and Steve Knight and Democrat Lee Rogers.
Why we're watching: Rogers, a doctor, took on retiring GOP Rep. Buck McKeon two years ago. Despite Republicans holding a slim advantage among registered voters in the Santa Clarita-centered district, it's difficult to imagine Rogers not advancing to another general election in November. That leaves either Strickland, a former state senator, or Knight, a current state senator, as the odd man out. Judging by the tone and tenor of the race, it's Strickland's to lose. He lost a bruising contest two years ago to freshman Rep. Julia Brownley in the neighboring 26th district. That came after two losses for state controller. He's got a lot of GOP establishment support, including endorsements from McKeon, as well as Mitt Romney, Rep. Darrell Issa and former U.N. Ambassador John Bolton.
Congressional District 31
Who we're watching: Democrats Pete Aguilar, Eloise Gomez Reyes and former Rep. Joe Baca and Republicans Paul Chabot and Leslie Gooch.
Why we're watching: The San Bernardino-based seat was a Democratic disaster two years ago, when Republicans Gary Miller and Bob Dutton clinched the top-two spots in a district that had been high on Democrats' November agenda. Could history repeat itself? As in June 2012, four Democrats are on the ballot. Much of the Democratic support has gone to Aguilar and Gomez Reyes, but Baca is trying to restart his congressional career. Democrats seem to be taking no chances, and the Democratic Congressional Campaign Committee cut loose with $85,000 in spending against Gooch, one of three Republicans running. Gooch and the other leading GOP candidate, Chabot, have much less money or name ID going for them than did Miller or Dutton. If a Democrat advances Tuesday, he or she would start the November campaign with the advantage in a district that President Barack Obama carried by 17 percentage points in 2012.
Congressional District 33
Who we're watching: Democrats Ted Lieu, Wendy Greuel, David Kanuth, Matt Miller, Republican Elan Carr and independent Marianne Williamson.
Why we're watching: This is as pure a tossup as there is on the primary ballot. Lieu, a state senator, got the party endorsement early and is stressing his family's rags-to-riches story. A former Air Force JAG prosecutor, his TV ad strikes a populist tone by promising he'd fight to keep the federal government from spying on ordinary Americans. Greuel, a former mayoral candidate and city controller, like many of the others in the race wants to expand on retiring Rep. Henry Waxman's legacy. Her campaign in recent days has taken aim at Lieu for alleged connections to disgraced Sen. Ron Calderon, D-Montebello. Lieu's campaign insists the attacks are baseless and will not resonate with voters. Miller and Kanuth have raised considerable amounts of money. Miller is a popular radio host, policy wonk and senior adviser in the Clinton White House while Kanuth is a public defender. Williamson, a self-help guru, would perhaps give Republicans the best chance at claiming the seat should she advance Tuesday. GOP Carr's resume is stocked. He prosecuted terrorists and insurgents and then in Los Angeles took on criminal street gangs. He has deep ties to the Jewish community and recently became a favorite of casino moguls and mega-donors Sheldon and Miriam Adelson.
Congressional District 52
Who we're watching: Democratic Rep. Scott Peters and Republican Carl DeMaio.
Why we're watching: DeMaio, a former city councilman who lost a close race to former San Diego Mayor Bob Filner, is a supremely skilled media practitioner. A self-described government reformer, lately he's painted himself as a "New Generation Republican," even featuring his same-sex partner in a television ad. DeMaio has said repeatedly that he doesn't want to play up social issues. At the same time, much of the national attention he's received &ndash and seemingly cooperated with – focuses on the fact that he's gay. Don't look for interest in his candidacy to subside past June. Last week, vandals ransacked his campaign office and the story was among the most read on key Washington publications. Peters, a former port commissioner, city councilman and environmental attorney, will likely spend the summer playing up his moderate bona fides while trying to highlight pre-"New Generation" DeMaio – a villain of local labor unions. The only question in the primary is whether DeMaio overcomes a pair of GOP challengers and finishes in first place.
PHOTO: Reps. Mike Honda, left, and Ami Bera, sing karaoke at an event in Washington, DC on May 7, 2014. Courtesy of Rep. Mike Honda's office