Montana's Republican Senate seat shifted into the Democratic column Wednesday afternoon, giving the party control of 50 seats and leaving Virginia as the lone roadblock to a Democratic sweep or a Republican split of Congress.

Democratic challenger John Tester claimed victory in Montana, besting three-term Republican incumbent Sen. Conrad Burns.

In Virginia, the State Board of Elections announced it would not certify the outcome of the race between incumbent Republican Sen. George Allen and Democratic challenger Jim Webb until Nov. 27, after which recounts could begin. There are no automatic recounts in Virginia. The candidates were separated by about 7,800 votes out of more than 2.3 million cast, with indications from both camps that any final outcome could wind up in court.

Republican and Democrat party officials dispatched lawyers to Virginia to observe vote counting, as well as to canvass votes counted on Election Day.

"No one is more interested in the outcome of this race then we at the Allen camp," said the Republican's adviser Ed Gillespie, who added that election officials are looking over their numbers for "mathematical mistakes, tabulation errors, juxtaposition of numbers" and other human error.

"The conclusion of the canvass will be the final official results," Gillespie said.

"I know the counting will continue through the night, it will continue tomorrow," Allen told supporters last night.

• Click here to visit YOU DECIDE 2006, FOXNews.com's complete election center.

• Check Your State, Check Your Race by clicking the BALANCE OF POWER dropdown menu above.

The too-close-to-call race didn't deter Webb, who bounded on stage just after 1 a.m. Wednesday to thank his supporters for a hard-fought victory.

"The votes are in and we won," Webb told a crowd of jubilant supporters at a northern Virginia hotel ballroom. "This is a great moment for all of us who believe in an inclusive society ... I will look forward to representing all of you to the best of my ability."

Allen's campaign had no comment, and FOX News, along with other major news outlets considered the race a virtual dead heat.

With the Montana vote decided, Democrats succeeded in shifting five Senate seats to their side of the aisle. A change of six seats into the Democratic aisle is needed to take the Senate out of Republican hands.

Democrats already were basking in the glow of victory Wednesday, fresh off capturing control of the U.S. House of Representatives, and in convincing fashion.

Democrats needed to swing 15 seats to take control, but by the end of the day they had won 26 seats.

Three GOP incumbents lost in Indiana, three more in Pennsylvania, two in New Hampshire, one in North Carolina, one in Kansas, one in California and more elsewhere. Democrats won open seats, which were held by Republicans, in New York, Ohio, Florida, Arizona, Colorado, Wisconsin, Iowa and Texas.

The Senate, however, proved to be a tougher mountain to climb.

In Missouri, Democrat Claire McCaskill had to wait until after 1 a.m. Wednesday to claim victory in a close race against incumbent Republican Jim Talent.

"All of our efforts fell a little bit short this time, but they were worth the making," said Talent, who was embroiled in a bitter debate about a proposed state amendment backing embryonic stem cell research.

Elsewhere, Republican Bob Corker defeated Democratic Rep. Harold Ford Jr., in the race for the Tennessee Senate seat being vacated by outgoing Senate Majority Leader Bill Frist.

In Pennsylvania, incumbent Republican Rick Santorum lost his seat to challenger Bob Casey. Republicans also lost a Senate seat in Ohio, when incumbent Sen. Mike DeWine was beaten by Democratic Rep. Sherrod Brown.

In Rhode Island, longtime Republican Sen. Lincoln Chafee lost to Democratic challenger Sheldon Whitehouse.

Dems: America Wants 'Change'

Click here for more on the House races

"It's a great night for Democrats, it's a great night for America," Sen. Charles Schumer, head of the Democratic Senatorial Campaign Committee, told supporters at the Hyatt in Washington around midnight Tuesday as Democrats celebrated their wins. "We will tell you and all of America, not only can we do better, but we will do better."

President Bush, meanwhile, called House Minority Leader Nancy Pelosi early Wednesday morning to congratulate her and her candidates on their win. The phone call was described as "cordial," and both reportedly pledged to work together.

Other phone calls were made to House Minority Whip Congressman Steny Hoyer, D-Md., and Democratic Congressional Campaign Committee Chair Rahm Emanuel, D-Ill.

Both Pelosi and Hoyer were invited to join the president for lunch at the White House on Thursday so they can "start to strategize on how to work together."

Pelosi is set to become the first female speaker of the House. Hoyer of Maryland announced he will run for the majority leader post, the second in command in the House.

The president also called House Speaker Dennis Hastert, who survived a surprisingly tough battle, and thanked him for running a tough campaign, assuring the embattled Illinois Republican that "we will all work together."

Hastert later disclosed to House Republicans that he had no intention of running for the House minority leadership post.

Hastert is preoccupied with the Mark Foley congressional page scandal, and questions about what he knew of Foley's electronic messages to under-age male pages.

Bush also called Senate Minority Leader Harry Reid, D-Nev., to congratulate him on "well run" Senate campaigns, as well as Senate Minority Whip Dick Durbin, D-Ill. Both Reid and Durbin were invited to the White House on Friday for a coffee meeting.

The White House described all the phones call with Democrats as a nature of "goodwill."

White House spokesman Tony Snow said Bush is "obviously disappointed" that the House changed hands, but pointed out that the president believes "the challenges haven't changed. Democrats have the responsibility to help the president win the war, and to keep the economy growing."

Click here to read more on the ballot initiatives

In the Senate, meanwhile, speculation grew regarding Lieberman's loyalty in spite of the long-time Democrats declaration Monday to FOX News that if elected as an Independent he would caucus with Democrats.

"Dear friends, this year's campaign, to say the obvious, was a long journey on which you — my dear supporters — and I were tested as never before but we never wavered in our beliefs or in our purpose, did we? And we never gave up, did we?" Lieberman asked supporters Tuesday night, thanking the labor groups and firefighters who made up a large portion of his base.

"And tonight, tonight, thanks to the voters of Connecticut, our journey has ended in victory and hope and the opportunity to make a difference for six more years," added Lieberman, who was shunned by fellow Democrats, including New York Sen. Hillary Clinton, a potential 2008 presidential contender.

In Maryland, Democratic Rep. Ben Cardin held off Republican Lt. Gov. Michael Steele for the seat vacated by retiring Sen. Paul Sarbanes. The race was called early for Cardin, but Steele refused to concede in spite of trailing by more than 152,000 votes.

One Steele campaign official told supporters to go home because they are not sure about the results.

"We do not believe we can calculate who won the race," the official said, adding that 200,000 absentee votes won't be counted until Thursday. "So, go home. We're going to pray."

In New Jersey, Democratic incumbent Sen. Bob Menendez beat Republican state Sen. Tom Kean Jr., son of the popular former governor and Sept. 11 commission chairman who shares his name.

Rep. Bernie Sanders easily captured the Senate seat in Vermont to keep it independent after the retirement of Sen. James Jeffords. Sens. Robert Byrd of West Virginia and Ted Kennedy of Massachusetts both went on to win record-breaking ninth terms.

In Florida, Democratic Sen. Bill Nelson handily warding off a challenge by Republican Rep. Katherine Harris. Her House seat stayed in GOP hands, though, going to businessman Vern Buchanan.

Click here to read more on the governors' races

Voters on Iraq, Corruption and Bush

As the final hours of Campaign 2006 wound down, the big question was how voter discontent would translate into control of Congress in the last two years of President Bush's administration.

Bush flew to his home state of Texas to vote, finishing a restrained five-day campaign swing in mostly GOP strongholds. But he was heading to bed with the Senate still hanging in the balance early Wednesday morning.

Just after leaving the White House Tuesday night, Snow pointed out that a number of so-called Blue Dog (conservative) Democrats were elected, saying that provides some "interesting opportunities." Snow said Bush will continue to push for "comprehensive immigration reform," among other issues.

Bush made one phone call on Election Night, and that was to Rep. Tom Reynolds, R-N.Y., to congratulate him on his re-election. Snow said the president will make the "rest of the calls" Wednesday morning, including a call to Pelosi.

FOX News exit polls of five key states — Arizona, Maryland, Ohio, Rhode Island and Virginia — released at 6 p.m. ET Tuesday, gave an early indication of voter sentiment.

Those polls of about 12,000 voters indicated 41 percent who cast their ballots approved of Bush's job performance, while 58 percent disapproved.

Of the 37 percent in the survey who said the war in Iraq was an extremely important issue in how they voted, 61 percent indicated they voted Democrat, while 37 percent said they voted for the Republican.

Meanwhile, of the 42 percent of those polled who said corruption and scandal in government was extremely important in their vote, 61 percent said they voted for the Democrat, while 36 percent went Republican.

One of the big questions in this campaign is whether it turns out to be a referendum on national issues or hundreds of separate races on local issues.

Thirty-three percent of voters said local matters counted most, while 62 percent focused on national affairs, according to the exit polls.

Spending by the two national parties surged in the final week as Democrats and Republicans invested in television commercials designed to sway the outcome in more than 60 House races and 10 Senate contests. In all, the two parties have spent about $225 million thus far in campaign activities independent of the candidates themselves.

FOX News' Bret Baier and The Associated Press contributed to this report.