Janice Hahn (left) and Debra Bowen are vying to replace ex-Rep. Jane Harman (D-Calif.)

Both California Secretary of State Debra Bowen and Los Angeles City Councilwoman Janice Hahn are touting their progressive credentials while trying to suggest the other is insufficiently loyal to the cause.

The likely result of the May 17 primary fight, which features 11 total candidates including 2010 primary loser Marcy Winograd, is a July 12 runoff. Under California’s new primary system, if no candidate gets 50 percent in the primary, the two top vote-getters, regardless of party, advance to a runoff.

“I think its clear there’ll be a runoff,” said Joe Trippi, a longtime Democratic consultant who is advising Hahn’s campaign.

Bowen holds statewide office and represented most of this district in the 1990s as a state legislator. Yet to hear her campaign tell it, she’s the outsider against Hahn.

The argument: Hahn has more endorsements and more money while Bowen has more grassroots support. A majority of her donors gave $200 or less. Democracy for America, a leading liberal organization, endorsed her after polling their members in the district. Her campaign is also quick to point out that Hahn has taken contributions from lobbyists.

As secretary of state, Bowen has been behind a number of initiatives that appeal to liberals, including work on ballot security. She has a long history of advocacy on environmental issues. She’s positioned herself as the anti-war candidate, trying to take some of the space occupied by Winograd, who ran against Harman in 2010 and took 41 percent.

“There is a clear choice here between somebody who is independent, who has integrity, who has results” versus a “city hall political operative ... who flip-flops, who doesn’t have conviction,” said Bowen’s communications director, Luis Vizcaino. (The flip-flopping charge is based mostly on Hahn’s support for, and then vote against, an initiative to tax oil extraction.) “[Bowen] is very intelligent, she is effective, and she is persistent,” said supporter Rep. Judy Chu (D-Calif.), who argued that Bowen’s small donor base gives her more opportunity to grow her war chest.

Hahn, on the other hand, has the endorsement of most top labor organizations. “You don’t collect the impressive array of labor endorsements across the spectrum that Hahn has garnered here if you’re some kind of political reactionary,” said Garry South, a Democratic consultant in the state. “Labor in L.A. County is very liberal.” He says its “bogus” to call a longtime establishment politician like Bowen the grassroots upstart.

In a special election with low turnout, labor’s help getting out the vote will be crucial. Hahn also has the support of Sen. Dianne Feinstein and Los Angeles Mayor Antonio Villaraigosa.

Winograd’s endorsement could also help in a runoff scenario. While current polling shows her support in the single digits, in a close runoff race her backing might be give either Bowen or Hahn the momentum boost they need to get over the top.

Republicans aren’t contesting the special election and the seat, as currently configured, is not competitive as President Obama carried it by 30 points in 2008.

With an independent commission set to draw the California congressional lines that will govern the 2012 House elections, it remains to be seen whether the eventual winner of the special election will have anything to worry about next November.