NBC News projects Democrat Jeff Merkley as the winner in the Oregon Senate race, ousting Republican incumbent Gordon Smith.
The victory was once considered unlikely against an incumbent who had highlighted his efforts to work across the aisle in hopes of surviving a wave of anti-GOP sentiment.
Smith's loss — the first for an incumbent Oregon senator in 40 years — means Democrats are poised to have at least 57 votes in the Senate next year. He had been the last GOP senator standing in the three Pacific Coast states south of Alaska.
"There's a lot of work for us to do together," Merkley told a crowd of supporters Thursday morning as they jammed a room at Portland State University and spilled into the hallway.
"It's time for a very different approach," he said, in such areas as health care, job creation, affordable housing and energy independence.
He was with his fellow Democrat, Sen. Ron Wyden, who said it wasn't an easy decision for Oregon to replace Smith.
Merkley, said Wyden, "is not just going to be a good Oregon senator, he's going to be a great one."
Smith spokeswoman Lindsay Gilbride said the senator called Merkley on Thursday morning to concede. By then, about 82 percent of the vote had been counted and Merkley led by more than 40,000 votes.
The margin had been closer before more vote totals started coming in from Multnomah County, which includes Portland. A flood of votes Oregonians delivered on Election Day have kept election workers tallying ballots for days.
For Merkley, it was a remarkable personal victory. The state House speaker and policy wonk from east Portland was far from the first choice of national Democrats looking for a challenger to Smith.
For Smith, the election represented a stinging rejection by voters of his political strategy. He ran TV ads touting his work with Barack Obama, Ted Kennedy and other prominent Democrats on issues such as alternative energy.
Merkley countered with a TV ad featuring Obama directly urging Oregonians to vote for Merkley. It was the only TV ad Obama had done for another candidate this year, showing the importance that national Democrats placed on the Oregon race.
There will be at least 55 Democrats in the Senate, plus two independents who align with them. The outcomes of three Senate races remain uncertain: A runoff election is to be held in Georgia, a recount is scheduled in Minnesota, and thousands of ballots remain to be counted in a close race in Alaska.
Smith planned a press conference in the afternoon.
A year ago, most observers doubted that Merkley could defeat the better-funded Smith. Merkley turned the race in his direction with millions of dollars from national Democrats and a campaign blitz that took him to 100 communities around the state.
Merkley told crowds that Smith was a Bush Republican who was more interested in bailing out Wall Street than helping people on Main Street.
He's the first Oregonian to oust an incumbent senator since Republican Bob Packwood ousted Democratic Sen. Wayne Morse in 1968.