Rep. Lynn Woolsey of Petaluma, who is retiring in 2012 after 20 years in Congress, has no plans to endorse a candidate for the new 2nd Congressional District stretching from Marin County to the Oregon border.

But Mike Thompson, a fellow Democrat from St. Helena who represents the neighboring congressional district, stepped into the fray last week.

He threw his support behind Jared Huffman, a San Rafael Democrat who has represented Marin and southern Sonoma County in the Assembly since 2006. Huffman already has forged a sizeable lead over the other five Democratic candidates in both campaign donations and endorsements.

In his endorsement, Thompson said Huffman is "the best choice to represent the North Coast in Congress."

Thompson is seeking his eighth term in an inland district, including Santa Rosa, created by a citizens redistricting commission for the 2012 election.

Huffman acknowledged he was not the only Democrat who sought Thompson's endorsement and winning it was "a hard sell, absolutely."

"He put all the candidates through the wringer," Huffman said.

Thompson said in an e-mail that he had met most of the candidates. "They had many questions for me. And I had many questions for them," he said.

An endorsement by Thompson, who is seen as a "heavy lifter" in Congress, is a "big coup" for Huffman, said David McCuan, a Sonoma State University political scientist.

Huffman, a former environmental attorney, is "a little more liberal" than Thompson, a member of the House Democrats moderate Blue Dog Coalition, McCuan said.

"They are much more similar than different," he said, but the relationship between the two "hasn't always been smooth."

Huffman's campaign strategy in piling up endorsements and donations is to "put space between himself and everybody else," McCuan said.

Adding Thompson and Assemblyman Wesley Chesbro, D-Arcata, last week, Huffman has endorsements from 31 current and former North Coast political leaders, as well as 21 labor, environmental and business groups.

Huffman held a substantial lead in campaign donations with $416,000 reported last month, followed by Stacey Lawson with $238,000 and Norman Solomon with $221,000.

Solomon, a Marin activist and author, cited 10 endorsements, including the Progressive Democrats of America, Rep. Raul Grijalva, D-Ariz., farmworkers advocate Dolores Huerta and Pentagon Papers whistleblower Daniel Ellsberg.

Lawson, a San Rafael businesswoman, said she will be announcing endorsements later.

Susan Adams, a Marin County supervisor, has endorsements from the American Nurses Association and California Association of Nurse Practitioners, as well as six North Coast political leaders.

Tiffany Renee, a Petaluma councilwoman, and William Courtney, a Mendocino County physician, have not announced any endorsements.

You can reach Staff Writer Guy Kovner at 521-5457 or