Bucking the role they play in most elections, Orange County voters will have clout in the upcoming midterm.

Control of the U.S. House of Representatives runs directly through California on Nov. 6. Four of the most competitive, closely-watched house races in the country happen to be in Orange County, where Democrats are fighting to take vulnerable GOP-held districts.

If Orange County Democrats can flip some or all of those seats, it’s likely the party will be on its way to getting the 23 it needs nationally to take a majority share of the House and, with it, a legislative-check on President Donald Trump for the remainder of his first term. Conversely, if county Republicans hold those districts, the odds are strong that the GOP will maintain control of Washington D.C. for another two years.

And beyond the top-of-the-ticket intrigue, many parts of Orange County will make down-ballot decisions that could be particularly important:

• Several city councils — a level of government dominated by the GOP even as party registration in the county has shifted from red to blue — are targeted by Democrats hoping to gain control.

• The future of Disney’s relationship with Anaheim is on the line in a couple of key votes.

• And, amid controversy and allegations of cheating that have roiled Orange County’s justice system in recent years, the races for the county’s top law enforcement posts – sheriff and district attorney – are the most competitive they’ve been in two decades.

Federal

All four of Orange County’s hyper-competitive congressional races are in districts where voters supported Hillary Clinton over Trump in the 2016 election. The contests already have attracted millions of dollars in outside spending from PACs and political parties, flooding local televisions and mailboxes with ads.

In the county’s inland 45th Congressional District, two-term incumbent U.S. Rep Mimi Walters (R-Irvine) is being challenged by Democratic UC Irvine law professor Katie Porter in a race of polar opposites. Walters is campaigning on her vote for Trump’s tax bill, saying it cut taxes for her constituents, while Porter vows to overturn the tax plan, saying it raises taxes on California homeowners and disproportionately helps the wealthy. And while Porter supports Medicare for All, Walters voted to repeal Obamacare. The 45th is one of only a half-dozen house races among 77 deemed “battleground” contests by Cook Political Report that will feature two or more women.

In the 48th, which covers much of coastal Orange County, Democrat Harley Rouda is challenging 30-year incumbent U.S. Rep. Dana Rohrabacher (R-Costa Mesa) in a battle that could directly reflect Trump’s popularity.

Rohrabacher is fighting to defend his turf by espousing hard-line immigration stances and tactics, much like Trump. Rohrabacher also has been linked to Russia and possible Russian meddling in the 2016 election, a cloud for the Trump presidency. Rohrabacher also has taken up the fight to regulate sober-living homes, an issue that touches his district. Meanwhile, Rouda has attacked the congressman as being ineffective and has advocated for bringing green-energy jobs to the district and for implementing a version of Medicare for All.

The two other battleground seats in Orange County – CA 39 and CA 49 – are open following the retirements of, respectively, Ed Royce (R-Fullerton) and Darrell Issa (R-Vista).

The 39th is considered among the most racially and ethnically diverse congressional districts in the country, where Latinos and Asians comprise two-thirds of the population and campaign ads can run in Chinese, Spanish and English. Navy veteran Gil Cisneros, a Democrat, is running against GOP former Assemblywoman Young Kim, a long-time aide to Royce.

Kim has highlighted her ties to Royce and locals, billing herself as the pro-business, hometown candidate. Meanwhile, Cisneros has attempted to saddle Kim with the GOP’s anti-immigration proposals, while advocating for universal health care and emphasizing his charity work. The district straddles parts of Orange, Los Angeles and San Bernardino counties.

The 49th – which spans Orange and San Diego counties – gave Issa and Republicans the narrowest house victory race in the nation in 2016, and it is projected as the GOP-held seat in Southern California that’s most likely flip Democratic. Republican Board of Equalization member and former Assemblywoman Diane Harkey, has campaigned on an anti-tax platform, highlighting her role as co-chair of the Gas Tax Repeal (Prop 6) initiative. Democrat Mike Levin, a San Juan Capistrano environmental lawyer and former executive director of the Orange County Democratic Party, is touting his clean-energy background and support of single-payer healthcare.

Countywide

Orange County’s justice system has experienced several high-profile miscues and scandals in recent years. Most notably, the U.S. Department of Justice launched an ongoing civil rights probe in 2016 after two courts ruled that Orange County sheriff’s deputies and prosecutors withheld evidence and improperly used jailhouse informants to illegally obtain confessions.

Those incidents set the backdrop for the most combative sheriff’s and district attorneys’ races in 20 years, in which self-described reformists are battling department insiders who continue to downplay recent problems.

In the race to replace retiring Sheriff, Sandra Hutchens, Undersheriff Don Barnes is running against Duke Nguyen, a public integrity investigator for the Los Angeles County District Attorney’s Office. Barnes, who has been in law enforcement for 29 years and has been a key leader in the department’s day-to-day operations in recent months, is campaigning on his public safety track record and his contention that the department’s problems have been overstated and are largely fixed. Nguyen says the sheriff’s department continues to threaten public safety and taxpayer wallets and promises to make it more responsive to minorities and the poor.

In the DAs race, 20-year incumbent Tony Rackauckas is being challenged by his longtime political nemesis, Orange County Supervisor Todd Spitzer. Spitzer has criticized Rackauckas for the informant scandal, which caused the DA’s office to be removed from the biggest mass murder case in county history and resulted in the killer, Scott Dekraai, being sentenced to life in prison, not Death Row. Meanwhile, Rackauckas has highlighted his office’s recent work fighting abuses in the sober living industry and highlighted Spitzer’s own controversies — including a 2017 loss in a wrongful termination suit, which cost the county $150,000, and a high-profile incident in which Spitzer carried a loaded gun into a restaurant to detain a fellow diner he felt was threatening.

In another contest that reflects the changing electorate in Orange County, a Democrat has a shot to win a seat on the Board of Supervisors for the first time in a decade. A win could give the party a voice in decisions about the county’s $6.5 billion budget, which includes funding for departments such as sheriff, health care and social services.

Republican Tim Shaw and Democrat Doug Chaffee, who respectively serve on the La Habra and Fullerton city councils, are competing for termed-out Supervisor Shawn Nelson’s open 4th District seat. While Democrats command a 10-percentage point voter registration lead in the district, lackluster turnout in recent midterms has helped Republicans hold the seat. Democrats hope the competitive congressional races will spur a jump in turnout among left-leaning voters, potentially providing a boost down-ballot, while Republicans hope Prop 6 — the bid to repeal the gas tax — will boost GOP turnout.

Local

Hoping for a “blue wave” of turnout, county Democrats have set a goal of taking control of four additional city councils this elections cycle – Anaheim, Buena Park, Costa Mesa, and Fullerton. Though Democrats hold a party registration advantage in 11 of 34 Orange County cities, the party currently holds a majority on only one city council, Santa Ana’s.

Some of the local contests will be conducted using a new format that could give grassroots candidates a better chance of winning. At least 15 cities and school districts in Orange County are set to hold their first elections using geographic voting districts rather than at-large bids – meaning voters will choose a single representative from one part of town rather than voting for several candidates citywide. Voters in two other cities – Santa Ana and San Clemente – will decide in November whether to switch from at-large to by-district elections.

Though every city council in Orange County will have some seats on the Nov. 6 ballot, races in two of the county’s biggest cities, Anaheim and Santa Ana, stand out.

Eight candidates are vying to replace Anaheim’s termed-out Mayor Tom Tait, and the city’s six-seat council could get as many as three new faces. After years of alternatively friendly and fractious dealings with the Walt Disney Co., the next council will determine Anaheim’s relationship with its biggest employer for the near future.

In Santa Ana, Ward 6 Councilman Sal Tinajero is challenging 24-year incumbent Miguel Pulido to take over as mayor. And two of the other five council members have reached their term limits. Those electoral decisions could significantly change the city’s legislative priorities.

Anaheim voters also will decide on a ballot measure that would require resort-area businesses that received city tax breaks to pay workers a minimum wage that would start at $15 an hour and increase by $1 annually until 2022. Although Disney recently tore up two subsidy agreements with the city, whether the measure would still apply to the company remains in dispute and could be litigated after the election.

At least five Orange County cities are asking voters to approve sales-tax increases to fund budget shortfalls. In Laguna Beach, a sales tax is proposed as a way to help finance a $135 million project to bury power lines within the city. But in Santa Ana, Garden Grove, Seal Beach, and Placentia, the tax will help pay for public safety costs amid growing pension payments and budget shortfalls.

State

Although seven Assembly districts and three state Senate district touching Orange County are up for grabs this election cycle, few of those contests are expected to be competitive.

In the race to replace Republican Assemblyman Travis Allen’s (AD-72) empty seat, GOP Westminster City Councilman Tyler Diep is running against Democratic businessman Josh Lowenthal. The race is projected as a toss-up despite Republicans holding a 4-point voter registration advantage.

Meanwhile, incumbent GOP State Senator Janet Nguyen is facing a challenge from Democratic businessman Tom Umberg. Democrats hold a 10-point voter registration advantage, but Nguyen, a moderate Republican, has overcome registration deficits in the past. An Umberg victory could give state Democrats the two-thirds supermajority they lost when Josh Newman was recalled from office in June.

Staff writers Alicia Robinson and Tony Saavedra contributed to this report.