PORTLAND, Ore. (AP) - Backed by national Democrats, Oregon House Speaker Jeff Merkley pulled out a victory Tuesday in the U.S. Senate primary, fending off a tough challenge from an insurgent opponent.

He'll face two-term incumbent Gordon Smith, the lone Republican senator on the West Coast, after defeating Portland lawyer and activist Steve Novick in the primary, 45.6 percent to 41 percent, with minor candidates capturing the remainder of the vote.

The seat is expected to be one of about a dozen that's targeted by Democrats hoping to get to a 60-vote majority in the Senate. National Democrats have already signaled their interest in the race, with the Democratic Senatorial Campaign Committee pouring $300,000 into television ads in the waning weeks of the primary as Smith ran his own ads attacking Merkley.

On Tuesday, Merkley picked up on the refrain of likely Democratic presidential nominee Barack Obama, who won a resounding victory in the Oregon primary on Tuesday.

"Together we can change the direction of our nation," he said, as the crowd roared back "Yes, we can," echoing Obama's now famous call-and-response line.

Merkley also hinted at the playbook Democrats will use over the next five months, linking Smith's name with President Bush as much as possible in his speech.

"We stepped forward to put America on the path of change, and on the path to Gordon Smith's and George Bush's retirements," he told his cheering supporters.

Smith, meanwhile, has launched a carefully orchestrated campaign to burnish his moderate credentials, taking out a full-page newspaper ad featuring Democrats who have endorsed him and running a campaign ad that stresses his independence while softpedaling his GOP ties.