How California’s primary could stop Democrats from retaking the U.S. House

California’s primary system could thwart Democrats and Republicans alike on June 5, shutting either party out of key races in the fall. Under the state’s top-two primary, the two candidates receiving the highest number of votes advance to the general election in November, regardless of party. Democrats fear that the high numbers of hopefuls on the primary ballot could split the vote and leave the party without candidates in high-stakes congressional races in November. Meanwhile, Republicans are worried they could be left off the ballot in the governor’s race and other statewide contests in November, giving their voters less of an incentive to turn out to vote for GOP House candidates.

Here's how the top-two primary system works

How could California's primary affect House races?

There are 435 seats in the U.S. House of Representatives. To regain the House majority, Democrats face a daunting task – they need to hang on to every seat they have, and then pick up a couple dozen more.

Every seat is on the ballot, but not every race is considered competitive. Only 69 out of the 435 seats have been identified as competitive by CQ RollCall. Nine of those competitive races are in California, where Democrats are hoping to flip several seats – if they make it on the ballot at all.

In some of these districts, the top-two system could result in two Republicans advancing from the primary to the general election, shutting Democrats out from crucial competitions in the fall. This outcome is possible in an open seat, or if an incumbent is facing a primary challenge. Using RollCall's ratings, There are five California primary races where this is a possiblity:

  • Ed Royce (Republican, CA-39)
  • Darrell Issa (Republican, CA-49)
  • Jeff Denham (Republican, CA-10)
  • Dana Rohrabacher (Republican, CA-48)
  • Duncan Hunter (Republican, CA-50)

These five seats are all currently held by Republicans, and if Democrats are forced out of these races for the general election, they'll have to pour more money and resources into races in other states that may be harder to win.

Turnout data gives California Republicans an edge

The number of registered Republicans in California reached an all time low in May, but primary election turnout – especially in non-presidential years – is notoriously low among Democrats and independents in California, while Republican turnout remains more consistent. According to a study from The Public Policy Institute of California, Democrats have gained more than a 6 percentage-point shift in general elections.

Percent Democratic vote shift from the primary to general election

This is consistent with research by Political Data Inc. (PDI), a for-profit company that partners with candidates and campaigns from both major parties, which suggests the statewide advantage for Democrats could drop by as much as 3 percentage points in the 2018 primary.

A lag in turnout could especially hurt Democrats’ prospects in the two open seat-races caused by the retirements of Darrell Issa and Ed Royce. In Royce's district, for example, there are only about 3,800 more registered Republican voters than Democrats. But PDI's turnout models that use past non-presidential primaries suggest there could be 15,000 more Republican ballots cast in June.

House races to watch

Open seat (incumbent Ed Royce)

39th District — Northeast Orange County, eastern Los Angeles County and part of San Bernardino County

There are a number of Republicans who stepped up to run for Royce's seat. Although former state assemblywoman Young Kim is widely considered the front-runner Republican, others in the GOP could capture enough of the vote to make it into the top two. Despite the fact that national Democrats have elevated lottery winner and Navy veteran Gil Cisneros, infighting between him and other Democratic candidates may weaken his chances of breaking through.

District voter registration: 34% Democratic | 35% Republican

PDI primary turnout prediction*: 36% Democratic | 46% Republican

2018 primary field

6 Democrats

7 Republicans

All candidates

Ted M. Alemayhu (AIP); Sophia Alexander (AIP); Gil Cisneros (D); Stephan Cox (NPP); John Cullum (R); Bob Huff (R); Sam Jammal (D); Young Kim (R); Herbert H. Lee (D); Suzi Park Leggett (D); Phil Liberatore (R); Shawn Nelson (R); Andrew Sarega (R); Karen Lee Schatzle (Ind); Andy Thorburn (D); Mai-Khanh Tran (D); Steven C. Vargas (R)

Previous election results

2014 primary

Ed Royce70.6%
Peter Anderson29.4%

2016 primary

Ed Royce60.5%
Brett Murdock39.5%

Open seat (incumbent Darrell Issa)

49th District — Southern Orange County and Northern San Diego

When Issa retired, a number of Republicans decided to run, including chairwoman of the state Board of Equalization Diane Harkey and Assemblyman Rocky Chavez. Meanwhile, there are four Democrats on the ballot, including two wealthy candidates who have self-funded their campaigns and spent on TV ads in the final weeks of the primary race. As the race has progressed, Democrats' worries that no clear front-runner is emerging have increased.

District voter registration: 31% Democratic | 37% Republican

PDI primary turnout prediction*: 37% Democratic | 44% Republican

2018 primary field

4 Democrats

8 Republicans

All candidates

Doug Applegate (D); Rocky Chavez (R); Kristin Gaspar (R); Joshua Hancock (Lib); Diane Harkey (R); Sara Jacobs (D); Paul G. Kerr (D); Mike Levin (D); Brian Maryott (R); David Medway (Rep); Jordan P. Mills (Peace and Freedom); Craig Nordal (R); Robert Pendleton (Ind); Mike Schmitt (R); Joshua Schoonover (R); Danielle St. John (Green)

Previous election results

2014 primary

Darrell Issa61.9%
Dave Peiser28.4%
Noboru Isagawa9.7%

2016 primary

Darrell Issa50.8%
Doug Applegate45.5%
Ryan Glenn Wingo3.7%

Dana Rohrabacher

48th District — Coastal Orange County

The threat to Democrats in this district is mostly because of one Republican challenger — Scott Baugh — a former assemblyman and county party chair who has enough prominence to glean votes from Republicans who might otherwise vote for Rohrabacher. A 15-term congressman, Rohrabacher's previously easy re-elections are no predictor given anti-Trump sentiment and a fresh spotlight on his longtime affinity for Russia and off-the-wall statements. Though national Democrats have signaled they prefer wealthy businessman Harley Rouda, eight will appear on the ballot and several of those are considered strong enough to split Democratic votes.

District voter registration: 30% Democratic | 41% Republican

PDI primary turnout prediction*: 32% Democratic | 49% Republican

2018 primary field

8 Democrats

6 Republicans

All candidates

Dana Rohrabacher (R); Scott Baugh (R); John Gabbard (R); Hans Keirstead (D); Kevin Kensinger (NPP); Michael Kotick (D); Paul Martin (R); Stelian Onufrei (R); Rachel Payne (D); Brandon Reiser (Lib); Harley E. Rouda (D); Shastina Sandman (R); Deanie Ann Schaarsmith (D); Omar Siddiqui (D); Tony Zarkades (D)

Previous election results

2014 primary

Dana Rohrabacher56.1%
Suzanne Joyce Savary19.5%
Wendy Brooks Leece11.9%
David Burns6.6%
Robert John Banuelos6.0%

2016 primary

Dana Rohrabacher56.6%
Suzanne Joyce Savary28.9%
Robert John Banuelos14.5%

Jeff Denham

10th District — Central Valley including Modesto

While Denham is likely to earn a place in the top two, voter registration here leans Democratic, making it possible, but less likely, that lesser known former Turlock City Councilman Ted Howze will also break through. Still, multiple Democrats are vying for the top two, several of whom have raised substantial campaign cash, though the party does not appear to have coalesced around a single candidate.

District voter registration: 39% Democratic | 36% Republican

PDI primary turnout prediction*: 41% Democratic | 43% Republican

2018 primary field

5 Democrats

2 Republicans

All candidates

Mike Barkley (D); Michael Eggman (D); Josh Harder (D); Jeff Denham (R) Ted D. Howze (R); Virginia Madueno (D); Dotty Nygard (D); Sue Zwahlen (D)

Previous election results

2014 primary

Jeff Denham58.9%
Michael Eggman26.4%
Michael Barkley14.7%

2016 primary

Jeff Denham47.7%
Michael Eggman27.6%
Michael Barkley14.5%
Robert Hodges10.2%

Duncan Hunter

50th District — Inland San Diego County

The embattled Hunter, who is under criminal investigation for possible campaign finance violations, is still running in a heavily Republican district, giving well-known Republican opponent El Cajon Mayor Bill Wells a decent shot at making the top two. Meanwhile, state Democrats have coalesced around former Department of Labor official Ammar Campa-Najjar, who received the state party's endorsement and is running alongside Democrat Josh Butner, a local school board member and retired Navy SEAL.

District voter registration: 27% Democratic | 42% Republican

PDI primary turnout prediction*: 29% Democratic | 52% Republican

2018 primary field

3 Democrats

3 Republicans

All candidates

Josh Butner (D); Ammar Campa-Najjar (D); Richard Kahle (Ind); Patrick Malloy (D); Duncan Hunter (R); Shamus Sayed (R); Bill Wells (R)

Previous election results

2014 primary

Duncan Hunter70.4%
James Kimber24.3%
Michael Benoit5.2%

2016 primary

Duncan Hunter56.5%
Patrick Malloy21.8%
David Secor11.5%
Scott Meisterlin6.8%
H. Fuji Shioura3.5%

*Turnout predictions are from PDI's 18P4 model, which assumes a universe of likely voters that have reregistered since November 2016, have voted in a primary election since 2010, or have voted in two previous elections since 2010.

In the governor's race, Republicans fear a depressed base

As Democrats battle against a shutout in key House races, Republicans are fighting to avoid the same fate in the governor's race. Even though a Democratic candidate is likely to win in the general election, an intraparty statewide race combined with a historically unpopular Republican president could drive down overall Republican turnout, giving Democrats an advantage in competitive House races.

In 2016, the first year with a major statewide race between two Democrats – Kamala Harris and Loretta Sanchez, who ran for a Senate seat – registration among Republicans in the state hit its lowest number for a presidential election year since 1984.

Republicans' best hope in the primary is John Cox, who was neck and neck with Democrat Antonio Villaraigosa in the latest poll from the Public Policy Institute of California.

However, a late-in-the game fundraising surge to Villaraigosa's campaign could give him an edge, shutting Republicans out of the biggest statewide race in November.

Sources: Previous election results from Ballotpedia and the California secretary of state. Turnout model data from Political Data, Inc. Governor polling data and Democratic vote shift data from PPIC.

Credits: John Myers and Julie Westfall contributed reporting.