The League of Conservation Voters has jumped into the Beaver State Senate race with a plea to voters to oust Sen. Gordon Smith (R) and elect state Speaker Jeff Merkley (D) to create a Democratic majority large enough to withstand a Republican filibuster.

The LCV, optimistic that Sen. Barack Obama (D-Ill.) will be elected president, urged Oregon voters to help the Democrats gain nine Senate seats in the upcoming election.

The LCV’s ad is designed to emphasize the point that a Democratic majority with 60 seats will be able to shepherd Obama’s energy and environmental agenda through Congress without having to worry about it being stymied by the GOP minority.

The 30-second spot is running statewide on cable television.

“Barack Obama will create new jobs and fight global warming. But he’ll need some help from Senators like Jeff Merkley,” a voice says in the LCV ad. “When you vote, don’t stop at the top. Give Barack Obama the team he needs for the change we need.”

Smith campaign spokeswoman Lindsay Gilbride noted that her boss worked with Obama in the Senate to pass an increase in government-mandated fuel-economy standards, adding that the Republican has long supported environmentally friendly legislation.

“Gordon Smith takes a back seat to no one in fighting for energy independence and a cleaner environment,” Gilbride said.