Fueled by a strong nationwide wave of support, Democrats in the Senate picked up five seats previously held by Republicans, expanding their control to at least 54 seats.

But races in Minnesota, Georgia, Alaska, and Oregon have yet to be called, all involving
Republican incumbents fighting to keep their seats.

If Democrats were to pick up all four seats, they could be within striking distance of a filibuster-proof majority of 60 seats, should the chamber’s two independents continue to caucus with the party. It remains to be seen whether Sen. Joe Lieberman, I-Conn., who campaigned for Republican presidential candidate John McCain, will continue to side with the Democrats.

Republicans had expected to suffer Senate losses but it wasn’t until the final weeks of the campaign that incumbents who previously looked to be secure were suddenly in trouble, such as Sen. Elizabeth Dole in North Carolina who lost her seat to state Sen. Kay Hagan.

In Oregon, where ballots are mailed in, the Senate race between Republican incumbent Sen. Gordon Smith and Democrat Jeff Merkley remained within a percentage point with 73 percent of precincts reporting. Adding to the mix is Constitution Party candidate Dave Brownlow with 5 percent.

In Georgia, Republican Saxby Chambliss, now faces a Dec. 2 run-off election with Democratic challenger Jim Martin. In Georgia, a candidate must win over 50 percent of the vote to avoid a run-off.

According to the Georgia Secretary of State’s unofficial results, Chambliss won 49.9 percent of the vote.

A run-off would be between Chambliss and Martin, and not include Libertarian candidate Allen Buckley who won 3.5 percent of the vote.

But the closest race may be in Minnesota, where another Republican incumbent Sen. Norm Coleman leads by 475 votes, a slim-enough lead to trigger a recount that is mandatory under state law if a race the margin is less than half of 1 percent.

According to unofficial results on the Secretary of State’s Office, Coleman has 41.99 percent of the vote to Franken’s 41.98 percent with 100 percent of precincts reporting. Independence Party candidate Dean Barkley won 15.16 percent.

Minnesota Secretary of State Mark Ritchie said a recount would begin in mid-November and may continue into December, according to the Associated Press.

Coleman claimed victory, but on Wednesday, Franken said the race was too close to call and that he would demand a recount.

Alaska Sen. Ted Stevens, who was convicted of federal corruption charges in late October, led Democratic challenger Mark Begich 48 percent to 46 percent, respectively, with 99 percent of precincts reporting. Thousands of absentee ballots remain to be counted, however, so the final result is still to be reported.

But even if Stevens wins, it’s unclear who would ultimately fill his seat.