Derek Bryson, left, a volunteer from Los Angeles, helps Erick Guillen, 25, of Simi Valley sign up to vote by mail. Democrats covet the seat held by Rep. Steve Knight, a Republican. (Christina House / For The Times)

Dan Henrickson rapped on the door of a stucco townhouse perched on a cul-de-sac in the north Los Angeles County suburb of Santa Clarita and awaited his fate.

The 63-year-old information technology consultant from Los Angeles was volunteering for the Democratic Party’s local club and still getting used to the awkward art of door-knocking — earlier in the afternoon, he choked on a sip of water just as a voter opened his door.

The man who answered this time looked Henrickson and his door-knocking partner up and down as they started their spiel. He asked them a single question: “Are you Democrats?”

The man shut the door when he got the answer.

California may offer Democrats a lopsided advantage as a whole, but this patch of the state — where the suburban sprawl of Los Angeles comes to an end and the Mojave Desert begins — is still a bastion for the Republican Party and the political territory of second-term GOP Rep. Steve Knight.

Knight won reelection by 6% last fall, but because Hillary Clinton was able to beat Donald Trump by about the same margin in his district, Democrats consider the seat as having prime pickup potential. The stakes: control of the House in 2018.

That is where Henrickson and about 90 other liberal activists come into the story, more than a year out from the election.

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Rep. Karen Bass, a Democrat from the Westside of Los Angeles, has been paying for buses and vans to ferry volunteers over the Sepulveda Pass into Santa Clarita, Simi Valley and the Antelope Valley to reinforce local Democrats as they start up voter registration drives. Organizers say they have registered 80 voters over three trips so far.

The volunteers are in no short supply. Many are political neophytes newly invigorated by opposition to President Trump and itching for something to do.

“In L.A., you kind of feel like you are in this helpless political bubble,” Zoe Ward, a 32-year-old student in UCLA’s film directing master’s program, said after scouring Palmdale for new voters on a recent Saturday. “Coming out here, it feels like my minutes and hours go further.”

Two weekend trips into the district earlier this spring show the task is grueling but uplifting work for some Democrats feeling guilty that they did not do enough in 2016 to help their party.

Henrickson came away with nothing to show for his time in Santa Clarita.

“I am not a big fan of it, but you got to do something,” he said. “The next time this is going to be easier.”

Organizers said they aren’t expecting much at first. Part of the program is simply letting locals know there are other Democrats around.

Simi Valley is, after all, home to the Reagan Presidential Library. Knight’s father, William J. “Pete” Knight, represented the Antelope Valley in Sacramento for 12 years and was the author of a successful 2000 ballot initiative banning gay marriage in the state. It might be easy for Democrats to feel they are lone liberals given how the district is steeped in conservative Southern California history.

“We want to let them know they are not alone,” said Christy Smith, a candidate for state Assembly in Santa Clarita who has taken part in the efforts. “For a long time they have felt like they need to stay inside their house with the curtains drawn and the doors closed.”

Mariah Craven, one of the organizers who also helped Kamala Harris win her Senate seat last fall, said Democrats have to start somewhere.

“This entire thing is very experimental,” she said. “There is no model for doing it this early.”

As the party looks to other districts like Knight’s — particularly in Orange County — that elected a Republican member of Congress and favored Clinton for president, they see bright spots for Democrats. They say they are ready to replicate the registration and outreach effort elsewhere.

If Democrats want to flip the district, first they have to build up their numbers: 37.6% of voters here are Democrats, 34.8% are Republicans and 22% decline to state a party.

In Knight territory, some volunteers are naturals, even professionals, at the art of building up the base.

Derek Bryson, a 56-year-old film editor from Culver City, sat on a park bench in Simi Valley clad in military-style hiking boots. He slurped down a protein shake. It was going to be in the high 80s that day.

His companion, Pamela Sparrow of Los Angeles, examined a granola bar and tossed it back on the table.

“Too salty,” she said. “That will dehydrate you.”

Both worked as paid field organizers for Clinton in Las Vegas, leaving California last year for a swing state that Democrats needed to keep to win.

Joining them were Laura Simon and her 14-year-old daughter Sofia, from Los Angeles. Simon said she stayed out of politics in 2016, and regrets it.

“I come for her future,” Simon said. “We are not going to make that same mistake again.”

Bryson and Sparrow jumped out of their car on a tree-lined street in Simi Valley. Nearby a shirtless man washed a raised 4×4 pickup truck.

“Every vote counts,” Bryson said to himself as they walked down the street.

Kris Rodriguez answered the first door they knocked on. The 25-year-old landscaper, clad in a T-shirt and sandals, squinted through his screen door and told them he’d never voted before.

“I really don’t care, to be honest with you,” he said. “I don’t know what party I am or what the difference is.”

Bryson switched to small talk about football, and after a moment Rodriguez took a look at the registration papers. A family member came over to help him. Bryson took a step back. After a moment Rodriguez returned the forms. He had registered as a Democrat.

Around the block, Bryson and Sparrow caught Erick Guillen on his way out the door The 25-year-old lab technician was bashful when he admitted he skipped last November’s election. Politics makes him uneasy.

“I didn’t feel like my voice would be heard or make a change,” he said. But he re-registered to vote by mail, saying he said didn’t like the way Trump’s tenure has started. “I am gonna vote now.”

The two were on a roll.

Tracy Stevens, 52, seemed puzzled when he saw the duo on his doorstep. “I thought you were gonna bust out the Bible,” he said.

He’d never had political canvassers come knocking and he took the opportunity to express his frustrations with the political system and how it “just doesn’t seem to matter” what people do to try to change things.