Neither Rep. Eric Swalwell, D-Dublin, nor Rep. Ro Khanna, D-Fremont, would have had a chance of reaching Capitol Hill if California voters had not ended the closed-primary system at the start of the decade. Swalwell would have been swamped by longtime Rep. Pete Stark in 2012, and Khanna would have been beaten by Rep. Mike Honda in 2016, and the two Democratic incumbents would have gone on to handily defeat their token Republican opposition.

It would have been end of story for the two challengers.

Instead, the voter-approved reform — which allowed the top two finishers to reach the general election, regardless of party — allowed these two young Democratic politicians an extended chance to make their case to the voters. Swalwell edged Stark in the 2012 general election, and Khanna gave Honda a close call in fall 2014, then prevailed soundly in 2016.

These two congressmen already are making their presence known in ways their predecessors never did.

Swalwell, a 36-year-old member of the House Intelligence Committee, has become a fixture on national cable TV shows with his insights on the investigations into Russian influence on the 2016 elections. He has emerged as a steadied, articulate Democratic voice who has not flinched at taking his call for an independent investigation to Fox News.

“I joked to Bill O’Reilly last week before the show, that that’s the only way my parents will be able to watch me, because they’re both Republicans,” he said, mindful that such a label also applies to a meaningful slice of his suburban district.

He has averaged nearly an appearance a day for the past month, from MSNBC to Fox News. By contrast, his predecessor Pete Stark’s rare splashes of national attention in his latter years of service were from his boorish outbursts, such as his suggestion that President George W. Bush was sending troops to Iraq to get their “heads blown off for their amusement” or for calling a female colleague a “whore for the insurance industry.”

Swalwell is getting serious attention for all the right reasons. He has been doing his due diligence on the Russian scandals. His congressional website’s graphic illustration of the connections between Russia and the Trump campaign and family has become a go-to source for news organizations tracking the issue. “This is the first time since I’ve been elected to Congress where I’ve been able to put my prosecutorial skills to work,” said Swalwell, a former Alameda County deputy district attorney.

I asked Swalwell where he thought this investigation might lead. The most favorable interpretation of the evidence to date for the president, he said, was that Trump showed poor judgment in surrounding himself with so many people with such close ties to an adversarial nation.

“At the very worst — what I want to know — was anyone on his team working with them, or did he know about it, or did he order it?” Swalwell said. That question remains very much open.

Swalwell, again unlike Stark, maintains a big presence in the district. Anyone who follows him on Twitter sees photographic evidence of his every-weekend trips back home, hitting community events large and small. “My wife is 31 weeks pregnant, so that’s another reason,” he added.

Meanwhile, Khanna, 40, has done his own tending to district issues. His recent town hall drew an overflow crowd of 1,000 — and he has another coming up, in a larger high-school venue.

“It just shows how engaged people are with the political process,” he said. “It’s an extraordinary time. ... There’s 1,000 people showing up who see me as between what Donald Trump is doing and their values.” Khanna also drew national attention on his recent trip to the heart of coal country, where he met with participants in a program to retrain out-of-work miners with software and website development skills.

“They talked about their love for coal, and being part of coal-mining families,” Khanna said. It’s important to understand that they still want coal, and they want those jobs ... but they also want to diversify.”

He saw the emergence of what the eastern Kentucky locals call “Silicon Holler” as a potential resource for companies in Silicon Valley.

“If we can make these connections between the bluest of blue areas and the red areas of the country ... that’s a step toward the type of healing our country needs,” Khanna said.

Swalwell has similarly made a point of transcending the partisanship that has debilitated D.C. One of his first moves in Congress was to help found the United Solutions Caucus, a bipartisan group of 30 members.

“I wish we had independent redistricting and a top-two primary in every state,” he said. ”I think you would have a better functioning Congress.”

It certainly brought change to these two congressional districts.

John Diaz is The San Francisco Chronicle’s editorial page editor. Email: jdiaz@sfchronicle.com Twitter: @JohnDiazChron

How they got elected: the role of voter-approved reforms

Ro Khanna and Eric Swalwell challenged long-serving Democratic incumbents. Each was defeated in the primary but finished stronger in the general election.

2012 primary

(U.S. House District 15)

Eastern Alameda County and part of Contra Costa County

Pete Stark (D)* 39,943 42.1%

Eric Swalwell (D) 34,347 36.2%

Christopher Pareja (NPP) 20,618 21.7%

2012 general election

Swalwell 120,388 52.1%

Stark 110,646 47.9%

2014 primary

(U.S. House District 17)

Western Santa Clara County, part of Alameda County

Mike Honda (D)* 43,607 48.2%

Ro Khanna (D) 25,384 28%

Vanila Singh (R) 15,359 17%

Joel Vanlandingham (R) 6,154 6.8%

2014 general election

Honda 69,561 51.8%

Khanna 64,487 48.2%

The close race gave Khanna momentum into 2016; he finished first in the primary and defeated Honda in the general with 61 percent of the vote.