Rep. Eric Swalwell, just two years ago a Democratic insurgent taking on his party's incumbent, now faces a role reversal.

The freshman lawmaker faces a challenge from state Senate Majority Leader Ellen Corbett, who attacks his lesser experience and Democratic bona fides much like Rep. Pete Stark did in 2012.

Now, however, Swalwell has the establishment's support -- up to and including President Barack Obama's. And Corbett, an influential veteran lawmaker with two decades of local name recognition and political experience, might face a steeper climb than Swalwell did as a first-term Dublin city councilman.

In 2012, Swalwell beat Stark on a shoestring budget. Now he has outspent Corbett three-to-one -- meaning more mail and television ads while still bringing the grass-roots door-knocking intensity he leveled against Stark -- and still has six times as much money remaining.

In 2012, Swalwell benefited from Stark's unfounded allegations, verbal gaffes and prickly personality. Now Corbett is less likely to get a similar leg up from the mostly affable, fresh-faced Swalwell.

And in 2012, after a conservative independent was eliminated in the top-two primary, Swalwell not only peeled Democrats away from Stark but also drew independents and Republicans who would vote for anyone but Stark. Now, Corbett -- a steadfast labor ally and indisputably liberal lawmaker -- is running to Swalwell's left, so if Republican Hugh Bussell doesn't make the cut in the June 3 primary, Swalwell again can appeal to a broader range of voters in November.

Swalwell should sweat "only if he's jogging," quipped Larry Gerston, a San Jose State University professor and political expert who sees little chance for Corbett.

"When an incumbent is challenged, it must be asked, 'Is there a reason to depose him or her?'" he said. "Swalwell has adhered pretty much to the values of the district. He has come home plenty. He's held all kinds of electronic town hall meetings."

Corbett "has been a good legislator" with strong ties to labor and other groups, Gerston said, "but there's only room for one, in the end ... and it's hard to see any real, concrete reason why someone like Swalwell would be voted out of office."

Extended benefits

Corbett suggests a few reasons.

She faults Swalwell's April 2013 vote for the Cyber Intelligence Sharing and Protection Act, which critics such as Corbett and Bussell say requires companies to give the government the personal Internet data of consumers without a warrant. "He can try to characterize it any way he wants, but that's what it does," Corbett said. "It shows that he's not in touch with the sentiments of the district."

Swalwell says CISPA isn't perfect, but it lets the government track hacking and data breaches without authorizing the kind of bulk data collection for which the government has been blasted in recent years. "The two could not be farther apart," he said.

Corbett also knocks Swalwell for not speaking out enough in favor of extending unemployment insurance benefits for long-term jobless people, and for not supporting two alternative liberal budgets that included such an extension. "When I saw the member of Congress for my district was not speaking out loudly about it, it was just too much for me," she said.

But Swalwell says he repeatedly wrote to urge House GOP leaders to allow consideration of an extension of jobless benefits last year; led 20 other Democrats in demanding an extension in mid-January; and was among the first cosponsors of a bill in April to restore the lost benefits. "Other than handcuffing myself to the speaker's chair and shutting down Congress in a Ted Cruz-like fashion, there's nothing else I could've done."

Swalwell counts among his proudest achievements roughly $1 million in benefits his office has helped secure for local veterans; his bill signed into law to incentivize typhoon-relief contributions for the Philippines; and his constant presence in the district and outreach to constituents.

"We're not taking the seat for granted at all; we're taking Ellen Corbett just as seriously as we took Pete Stark. She should be taken seriously; she's been in elected office for 20 years," he said, explaining that he says "we" because "I don't like to take credit solely for anything we've done."

"But we're bringing the new energy and ideas that the voters here want," he said. "We showed that you can reject some of the entitled old-guard approach when we earned this seat last time."

Job brakes

Corbett says her experience as a lawmaker, running a small business and raising her son makes her a stronger candidate than Swalwell. "It is important to have experience, and it's important to have a record to run on," she said. "I've had the opportunity to hone the skills to be an effective legislator, and to know the hopes and dreams of my constituents."

She won and kept her state Senate seat by solid margins, but was too embedded in the same party and labor circles as Stark to challenge him in 2012 as Swalwell did. Most labor unions and local Democratic clubs now support her, though the state Democratic Party endorsed Swalwell.

The Democrats agree on many issues.

Swalwell and Corbett said they support making the wealthiest pay their "fair share of taxes" while Bussell says high taxes and heavy regulation have "put the brake on job creation" and produced a sluggish economic recovery. Swalwell and Corbett favor comprehensive immigration reform, including a path to citizenship for those already here, while Bussell -- though open to legalizing some undocumented immigrants, especially those brought here at a young age -- wants the nation's borders secured before anything else happens.

Bussell knows it's unlikely he can win, but said it's important that he do the best he can to voice conservative principles. He said Swalwell seems more interested in a political career than in the people he serves, while Corbett has contributed to California's fiscal woes.

Josh Richman covers politics. Contact him at 510-208-6428. Follow him at Twitter.com/josh_richman. Read the Political Blotter at IBAbuzz.com/politics.

15th congressional district candidates

Name: Eric Swalwell
Party: Democrat
Age: 33
Residence: Dublin
Education: Bachelor's degree in government and politics and law degree, University of Maryland
Experience: Congressman, 2013-present; Dublin councilman, 2010-12; Dublin Planning Commission, 2008-2010; Alameda County deputy district attorney, 2006-2012
Website: www.swalwellforcongress.com

Name: Ellen Corbett
Party: Democrat
Age: 59
Residence: San Leandro
Education: Bachelor's degree in political science, UC Davis; law degree, University of the Pacific
Experience: State senator, 2006-present; state assemblywoman, 1998-2004; San Leandro mayor, 1995-1998; San Leandro councilwoman, 1991-1995; attorney, 1987-98
Website: http://corbettforcongress2014.com

Name: Hugh Bussell
Party: Republican
Age: 55
Residence: Livermore
Education: Bachelor's degree in physics, UC Berkeley; California teaching credential, San Francisco State University
Experience: Alameda County Republican Central Committee, 2009-present (currently vice-chairman); software content development manager, technical writer and training manager; former math and science teacher at James Logan High School in Union City and at Albany High School in Albany
Website: www.bussellforcongress.org