Democrat Katie Hill unseated Republican Steve Knight by a surprisingly comfortable margin in the most-watched congressional election in Los Angeles County last November. She has gained an unusually high profile for a freshman member of the House of Representatives since arriving in Washington, D.C. And she’s off to a good start on fundraising for her first re-election campaign.

None of that seems to be discouraging Republicans from aiming to recapture the 25th District next year.

Angela Underwood Jacobs, Suzette Martinez Valladares and Mike Garcia already have filed papers with the Federal Election Commission to run in the March 3, 2020 primary. More could enter the race in the months ahead.

The three GOP candidates argue that Hill has quickly fallen out of step with the once solidly conservative district that covers parts of the San Fernando, Santa Clarita, Simi and Antelope valleys.

“Katie Hill’s performance in the first four months proves she’s not as moderate as she advertised herself to be,” said Garcia, who contends Hill is “voting in lockstep with (New York Rep.) Alexandria Ocasio-Cortez to push a socialist agenda.”

“From what I can tell, she’s a socialist. I’m a conservative,” Underwood Jacobs said.

“She’s gone to Washington and really sold out to the progressive wing of the (Democratic) Party,” Valladares said.

Hill fired back, saying she has passed bipartisan bills — to establish a memorial at the site of the 1928 St. Francis Dam disaster, and to expand whistle-blower protections — and addressed community issues involving military housing, law-enforcement resources and health care.

“Clearly these candidates are taking their talking points from D.C. special interests,” Hill said. “Frankly, it’s disappointing to see them entering the race playing the same political games I ran against. I’m confident our community knows that I’m working for them.”

Each GOP candidate argues that she or he has the background most likely to impress voters in a general-election contest against Hill on Nov. 3, 2020.

• Valladares, 38, an Acton resident with a 2-year-old daughter, is a former district director for then-Rep. Buck McKeon, and is CEO of a faith-based non-profit that provides childcare and preschool in L.A. County. In an interview, Valladares called herself a “modern Republican,” interested in issues such as health care that don’t traditionally interest the party’s politicians. She said that as a young, Latino woman, she would appeal to a majority of the residents in CA-25, which is about 35 percent Latino.

Valladares said she decided to run because she worries about her child’s future.

“I want to make sure she grows up in a country that is safe,” said Valladares, who blames Congress for failing to secure the Mexican border. “I want to make sure the schools she goes to offer her a quality education. I want to make sure the government’s role in her life is limited and allows her to be her own individual and pursue her own future.”

Valladares said she supports most of President Trump’s policies but opposes most of his tactics, such as Trump’s emergency declaration to free up money to fund a border wall.

• Garcia, 42, a Valencia resident with two sons, was a Navy lieutenant commander who flew more than 30 combat missions in the Iraq war. He has worked in real estate and for the Raytheon Company in the business development division. Garcia thinks his military background will connect with voters in a district with a heavy veteran and aerospace presence.

“I’ve always had patriotism in my DNA, and on the heels of the last election, I felt the results did not align with the values of the 25th District,” Garcia said. “I decided I would get in and run.”

Garcia said national security policy is at “an inflection point,” and that the House majority Democrats secured in 2018 threatens gains he said Trump has made on defense strategy and funding.

• Underwood Jacobs, 53, a Lancaster resident and mother of a son and daughter, is a Lancaster City Council member, and a bank regional manager after working her way up from a job as a teller. She said voters will reward her for the reputation she has built in city government.

“I think, at the end of the day, people want to know someone is fair, compassionate and empathetic, and that they truly mean what they say,” said Underwood Jacobs, who said she has promoted business growth in the Antelope Valley.

Underwood Jacobs, who is African American, said she voted for Trump in 2016 and “more than likely” will vote for him in 2020.

“I like the way the country is headed,” she said. “I feel more secure now as a mother than I have in years past.”

Hill won by 8.8 percentage points over Knight, who probably was harmed by his votes to support Trump’s tax-cut plan and to kill the Affordable Care Act.

The 31-year-old Agua Dulce resident quickly became a familiar face on political TV, was named one of two freshman caucus representatives to House leadership, and became vice chair of the powerful House Committee on Oversight and Reform.

National observers expect the 25th District race to be competitive in 2020. But they give the Democratic incumbent a clear edge in a district, spanning the L.A.-Ventura county line, where Democratic registered voters outnumbered Republicans by 4.8 percentage points in February after trailing as recently as 2014.

Three prominent election forecasters — the Cook Political Report House Ratings, the Roll Call Election Guide, and University of Virginia professor Larry Sabato’s Crystal Ball — all rate the 25th District as “likely Democratic” in their first round of analysis for 2020.

In analysts’ vernacular, “likely Democratic” is one step more emphatic prediction than “leans Democratic.” According to a consensus of the three forecasters, Hill is the second most likely winner in 2020 among the seven California Democrats who flipped formerly Republican districts in 2018. The only more likely winner, the forecasters suggest, is Mike Levin, D-San Juan Capistrano, whose 49th District is rated “likely Democratic” by the Cook Report and “solid Democratic” by Roll Call, and is not listed among competitive races by Sabato.

The parties, however, view all seven districts as battlegrounds.

In February, the National Republican Congressional Committee put the California districts held by Hill, Levin, Josh Harder, T.J. Cox, Gil Cisneros, Katie Porter and Harley Rouda on its list of 55 Democratic seats to target in 2020, and the Democratic Congressional Campaign Committee put them all on its list of “vulnerable” seats to defend.

Hill said she has raised $560,000 in the first quarter of 2019, a figure that campaign spokeswoman Lindsay Bubar said should rank among the top 10 for House incumbents when the FEC posts official fundraising reports next week.

Larry Becker, a Cal State Northridge political science professor, said a member of Congress can be vulnerable in her first bid for re-election because she hasn’t had time to build up accomplishments. But Becker said Hill seems “well positioned” for the 2020 race.

Although having Latino and African-American candidates might broaden the GOP’s appeal in the increasingly diverse district, Becker said, voters will pay more attention to policies. He questioned labeling Hill “socialist.”

“It’s especially silly in the case of Katie Hill,” Becker said. “She’s not a wild-eyed progressive in the ilk of Alexandria Ocasio-Cortez.

“You can use the label all you want, but I don’t think people are going to see Katie Hill that way.”

The deadline for declaring a candidacy for Congress in 2020 is Dec. 6, 2019.