WASHINGTON — Democrats added another Senate seat yesterday when they squeaked out a victory in Oregon, leaving only three contests undecided.

Democrat Jeff Merkley, a state legislator, defeated two-term Republican Sen. Gordon Smith by about 40,000 votes. Smith called Merkley to concede.

"This is the beginning of a transformational change for America," Merkley told supporters.

His win means Democrats will control 57 of the Senate's 100 seats, still short of a filibuster-proof 60-vote majority, which would enable them to leap Republican hurdles to their agenda more easily.

"We thought 56 votes was enough to pass real, meaningful legislation," said Matthew Miller, a spokesman for the Democratic Senatorial Campaign Committee. "Fifty-seven is all the better."

Still undecided are races in Alaska, where votes remain to be counted; Minnesota, where there will be a recount; and Georgia, where there probably will be a runoff.

Sen. Ted Stevens, an Alaska Republican who's been in Congress since the 1960s, was leading in his bid for an eighth term, but with felony convictions for corruption hanging over his head.

He's ahead of the Democrat, Anchorage Mayor Mark Begich, by more than 3,000 votes, but more than 55,000 remain to be counted.

Regardless of the final tally, Senate Majority Leader Harry Reid, a Nevada Democrat, has said, "The reality is that a convicted felon is not going to be able to serve in the United States Senate. And as precedent shows us, Senator Stevens will face an Ethics Committee investigation and expulsion, regardless of his appeals process."

Out of nearly 3 million votes cast for the Senate in Minnesota, Republican incumbent Norm Coleman has a 438-vote lead over Democrat Al Franken, a former writer for "Saturday Night Live."

Coleman declared victory when his lead was 725 votes, but it's since been dropping. He urged Franken to forgo a recount, automatically triggered when the margin is so slim.

However, Franken told Minnesota Public Radio yesterday, "This is the closest race in Minnesota history. This is part of the process to make sure every vote is counted fairly."

Three percentage points separate the candidates in the Georgia Senate race, where votes are still being counted.

Neither Republican incumbent Saxby Chambliss nor Democrat Jim Martin has received enough to meet the state-required minimum of 50 percent plus one to be declared the winner. Chambliss has received 49.8 percent and Martin 46.8 percent. The state is expected to hold a runoff Dec. 2.