Sen. Steve Hobbs, D-Lake Stevens, will be facing another familiar challenger this year – and this one is a fellow Democrat.

Lillian Kaufer of Snohomish, who lost to Hobbs in the Democratic primary in 2006, plans to file paperwork today to face him again. Hobbs is already facing the Republican he unseated from the Senate seat in 2006, Dave Schmidt. A second Republican, Ryan Ferrie is also seeking the position in the 44th Legislative District.

Rep. Hans Dunshee, D-Snohomish, had been contemplating running for the seat but decided to seek re-election instead.

Kaufer is an unabashed liberal with a passion for politics. You can see it in this photo (which she explains her reaction here ) and read it in this letter.

Kaufer’s entry marks a U-turn for her this campaign season and one welcomed by Hobbs’ detractors.

For weeks she had been running against Republican Rep. Mike Hope, R-Lake Stevens, and had raised nearly $5,000 for that effort. She called it off shortly after another Democrat, John Boerger, secured the Democratic Party’s nomination in that contest.

Even before then, she said, it didn’t feel like the right race. She said it was going to be tough to raise enough money to mount a viable campaign because members of the House Democratic Caucus and several labor unions made clear they weren’t planning to invest a lot of cash into trying to unseat Hope.

Hobbs is another story – at least for party liberals and union members. They’ve criticized Hobbs for voting against new tax revenues and important labor-backed legislation. His role in helping form a coalition of moderate House and Senate members known as the Roadkill Caucus has made him even more of a target.

Kaufer sounded confident those dissatisfied with the freshman senator may open their wallets wider to help her. She has met with members and leaders of the Washington Education Association, Service Employees International Union and Washington State Labor Council.

Teacher and health care worker unions didn’t like Hobbs’ votes on bills dealing with education reform and unionizing of child care center workers. Some members actively courted Dunshee to run.

Ben Lawver, political director of the Washington State Labor Council, said members of his group feel “betrayed” by Hobbs whom they supported in the 2006 election. (WEA and SEIU endorsed Schmidt for re-election in 2006.)

“We were the only group putting our neck out for him,” Lawver said. The Roadkill Caucus proved to be more of a voice for business than the working class and that didn’t sit well with members, he said.

Kaufer would have a “pretty good shot” at getting the labor council endorsement in mid-May, Lawver predicted.

Kaufer, 42, and her husband own a vending machine business known as Kaufer Vending.

Four years ago, when she faced Hobbs, she had the endorsements of Dunshee, then Democratic Rep. John Lovick (he’s now the Snohomish County sheriff) and the Senate Democratic Caucus. She ended up losing the Democratic primary to Hobbs by 635 votes.

She’s pumped up for another shot.

“He wants to be in the middle and you have to stand for something,” she said. “People are upset enough that I have a real chance to make a difference.”

Kaufer described Hobbs as “Republican-light” with a voting record that represented a “full frontal attack on working people.”