Missouri Democratic Sen. Jean Carnahan conceded to former Rep. Jim Talent just after 2 a.m. EST, handing the Republicans the last win they needed to regain the control they lost when Vermont Sen. Jim Jeffords bolted from the GOP in 2001.
"I have just called Mr. Talent and conceded this race," Carnahan told supporters at the early morning campaign rally.
In the highly competitive midterm elections where Republicans needed a net gain of only one seat in the Senate, the GOP also picked up a key victory in Georgia and looked poised to win another in Minnesota when all the votes are counted, by hand, in the race between Republican Norm Coleman and Walter Mondale.
Democrats did manage to pick off one seat from the GOP -- Sen. Tim Hutchinson conceded to Democrat Mark Pryor in Arkansas.
"If Republicans are able to gain seats in the Senate, it will be the first time in history the Republican Party will have taken over the Senate in the first midterm of a presidential term," White House spokesman Ari Fleischer said right before Carnahan took the stage in Missouri. "So by all accounts, the night is going very well."
President George W. Bush had embarked on a major campaign push over the past five days, hitting 15 states to stump for GOP candidates seen as in possible trouble. Political analysts had wondered whether Bush's efforts would translate into enough ballots to push the GOP back into the majority in a race that few were willing to speculate on.
"We're certainly delighted with what has come through so far, but there is a lot left to unfold. We've always had the belief that retention of the House and picking up the Senate were within our grasp as long as we worked hard and presented a message that resonated in the lives of the people," said Marc Racicot, chairman of the Republican National Committee.
In an interview before Carnahan's concession, Sen. Barbara Boxer, D-Calif, commented late Tuesday on the prospect of a GOP majority in Senate.
She told KCAL-TV in Los Angeles that she is concerned that the Republicans will attempt to roll back environmental laws and women's rights and also appoint overly conservative judges.
"I'm very fearful of that, so we are going to have to be very vigilant," Boxer said.
Other contentious seats in the Senate were set to remain with their respective parties: Republicans led in South Carolina, North Carolina, New Hampshire and Colorado. Democrats were holding their own in New Jersey. South Dakota remained undecided early Wednesday.
New Democrat Network President Simon Rosenberg said it was a close night that showed the country remains very evenly divided between the two parties. He stressed that the party had won some important governorships, but that there were also some disappointing losses.
"We'll take a look at what went right, what went wrong, and learn our lessons to prepare for 2004," Rosenberg said.
The Senate is currently split between the GOP and the Democrats, which hold 49 seats each, and two independents -- Jeffords of Vermont, and Dean Barkley, appointed by Minnesota Gov. Jesse Ventura to fill the vacancy left by the death of Sen. Paul Wellstone last month.
Because the vice president breaks any tie vote in the Senate, Republicans needed a net gain of only one seat to get control of the chamber. Carnahan conceded that gain and the GOP waited on more in the early morning hours.
Tracking the results became more complicated Tuesday evening when Voter News Service, a consortium of major media organizations that conducts and analyzes exit polls, pulled the plug entirely on its predictions, as the analysis of the data was deemed unreliable. The networks and reporters were left watching official results.
All eyes were on a number of key races that would determine the partisan makeup of the upper chamber during the next congressional session. Among those closely watched races are Missouri, Georgia, Arkansas, Minnesota, South Dakota, South Carolina, New Hampshire, Colorado, Texas, Louisiana and Iowa.
Elizabeth Dole was one of the early winners of the night, defeating Democratic challenger Erskine Bowles. Dole beat former President Clinton's ex-chief of staff for the seat to be vacated by retiring Sen. Jesse Helms, also a Republican.
"We'll never forget this night, will we?" Elizabeth Dole told a cheering crowd in Salisbury, N.C., just after 10 p.m. "Just a few minutes ago I received a call from Erskine Bowles. He congratulated me on this victory."
In New Hampshire, GOP Rep. John Sununu -- son of former President Reagan's chief of staff -- beat his Democratic rival, Gov. Jeanne Shaheen. "It was a tremendous grass-roots operation that made this victory possible," said Sununu.
Democrat Frank Lautenberg announced his Senate victory over Republican challenger Douglas Forrester. Lautenberg stepped in to replace Sen. Robert Torricelli, who dropped out as his poll numbers plunged in the wake of an ethics scandal.
Arkansas Attorney General, Democrat Mark Pryor defeated incumbent Sen. Tim Hutchinson. Hutchinson had lost support in his conservative base after divorcing his wife of almost 30 years to marry and aide more than two decades his junior.
Former Vice President Walter Mondale returned to Minnesota to continue the Senate run in Wellstone's stead. The 74-year-old Mondale is up against a younger Republican, Norm Coleman.
In South Carolina, Republican Rep. Lindsey Graham led Democrat Alex Sanders.
Republican Sen. Wayne Allard also fought off a challenge from Democrat Tom Strickland in Colorado and Democrat incumbent Sen. Mary Landrieu is headed for a Dec. 7 runoff election in Louisiana because she failed to gain more than 50 percent of the vote in the state.
And in Iowa, Democratic Sen. Tom Harkin was beating back Republican Rep. Greg Ganske.