State Speaker Jeff Merkley has picked up another key union endorsement as he seeks to maintain his advantage in the Democratic Senate primary and build momentum for a likely general election challenge of Sen. Gordon Smith (R).

Merkley, who is favored to defeat attorney Steve Novick in the primary, was endorsed this week by the Oregon AFL-CIO, the state’s largest labor union coalition. The state federation has 145,000 members.

“Jeff Merkley is a hero for all Oregonians who work to support their families,” Oregon AFL-CIO President Tom Chamberlain said in a statement.

Last month Merkley received the backing of the American Federation of State, County and Municipal Employees Council 75, a union of 22,000 government employees in the Beaver State.

— David M. Drucker