Jeff Merkley claimed victory Thursday and threw himself into his role as senator-elect, saying he's ready to join other Democrats on a "bold agenda" to remake the nation's policies and image.

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"This is the beginning of a transformational change for America," Merkley said in an acceptance speech at Portland State University's Urban Center.

Sen. Gordon Smith, meeting with reporters at his home in Pendleton, conceded the race and offered to help Merkley prepare for his new job.

Merkley, 52, said he would become part of a new "working majority" in the Senate that would help President-elect Barack Obama usher in universal health care, a national energy policy that attacks global warming and an end to the Iraq war.

"It's time to go change the world," he told a cheering group of his campaign staff and other supporters. "Let's do it together."

The five-term state legislator defeated Republican Sen. Gordon Smith by 3 percentage points, 49 to 46, and unseated an incumbent Oregon senator for the first time in 40 years.

It was a close, bitterly fought contest that set new records for political spending in Oregon: $45 million in all. The money paid for a barrage of negative ads, many of them produced by groups outside the national Republican and Democratic parties.

The election ended Smith's 16 years in office -- four as a state senator and 12 in the U.S. Senate. During his tenure in Washington, Smith gained a reputation as a moderate who crossed his party to support issues such as stem cell research and legislation against hate crimes.

In 2003, Smith's son, Garrett, committed suicide after a long, traumatizing battle with depression. The episode prompted Smith to champion mental health legislation.

In an interview with The Oregonian before his concession, Smith ruled out a run for governor in two years, as some have suggested.

"I have no plans," Smith said, relaxing for a few minutes between phone calls beside a fireplace in his brick home on a Pendleton hilltop.

"I don't know what I'm going to do yet. I'm going to enjoy getting my boots back on and getting back in the pea fields," he said. Smith, 56, owns Smith Frozen Foods, a vegetable packing company started by his father.

It was an emotional day. Smith took 15 minutes for a conference call with staffers in Washington D.C., choking up as he thanked them for their friendship and their work on his behalf.

Later, he held a press conference with his wife, Sharon, beside him. "It has been a remarkable 12 years," he said, "filled with calamities that have tested us all."

Smith expressed regret at the toughness of the campaign ads by both sides. Such ads run counter to his nature, he said, adding, "This isn't beanbags, it's hardball."

Merkley, too, got misty-eyed as he celebrated his win with supporters. To rousing cheers, he kissed his wife, introduced his 81-year-old mother and talked about how his father, a former millworker who died last year, reared him on politics.

"His voice about building a better America for working families will be in my head every day as I serve," Merkley said.

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A half-hour later, Merkley joined Sen. Ron Wyden, D-Ore., and a group of city and county officials to call for spurring the economy by investing billions of dollars in the nation's highway and mass transit systems.

Merkley said he has begun talking to Senate leaders about his transition, including a request to be on the committees for Appropriations, Energy, Environment or Health, Education and Labor.

Merkley, who has two school-aged children, said his family would remain in Portland for the remainder of the school year, then decide whether to move to Washington. His campaign spokesman, Matt Canter, said the family plans to take the weekend off -- their first vacation since Merkley started campaigning a year and a half ago.

Next week, Merkley probably will take a trip around the state, sometimes called a victory lap, to talk about his Senate plans.

Merkley's victory knocked out the West Coast's last remaining Senate Republican. It also made a political orphan of U.S. Rep. Greg Walden, now the only Republican in Oregon's delegation.

"I'm now part of a protected class under the Endangered Species Act," Walden joked. "I'm growing more fond of that law every day."

He said losing Smith would be tough on him personally and for Oregon politically. "Seniority counts, especially in the Senate."

But Merkley's election drew praise from a range of groups, including abortion rights and environmental organizations. Gov. Ted Kulongoski, a fellow Democrat, said Merkley will be a quick study in the Senate.

"He is a very strong humanitarian," Kulongoski said. "I think you're going to see him become a very, very strong advocate around health care and around the issue of the poor and underserved. That's who he is."

Richard Cockle of The Oregonian contributed to this story.

-- Harry Esteve; harryesteve@news.oregonian.com