Republicans increased their majority in the U.S. Senate on Tuesday, capturing Democratic seats in North Carolina, South Carolina and Georgia, finishing in a strong position to maintain control.

The highest-profile Senate race remained undecided into the wee hours Wednesday morning, with minority leader Tom Daschle of South Dakota fighting to keep the seat he has held for 18 years out of the hands of Jim Thune, a former House member.

The South Dakota race was the most expensive Senate contest in the nation, at about $50 a head for the state’s estimated 500,000 registered voters, the Associated Press reported. Combined, the two candidates spent $26.3 million. The last time a politician unseated a Senate leader was 1952, when Barry Goldwater of Arizona defeated Ernest McFarland.

Thirty-four Senate races were contested this year, with Republicans defending 15 seats and the Democrats, 19.

Alaska and Florida residents were also awaiting results early Wednesday, though political analysts said the extra Republican seats would likely do little to move more legislation through Congress.

“In the case of a filibuster, you need 60 votes to stop it,” said Sanford Gordon, assistant professor of political science at New York University. “So in order to get anything done in the Senate, you need to get not the 51st person to vote with you, but the 60th person.

“As long as there is no huge majority, there are procedural limits on what can be accomplished as far as legislation.”

As predicted, Barack Obama won his state handily against Alan Keyes, winning the votes of 70 percent of the electorate in Illinois.

“Nobody thought we had a chance,” Obama said in a written statement. “People said: ‘He can’t win, he’s got no money, no organization, and no one can pronounce his name.’ But you told them loud enough so that the whole state could hear: ‘Yes, we can.’”

Obama took over a Republican seat and will be the only black senator come January.

In Florida, Mel Martinez, former secretary of the U.S. Department of Housing and Urban Development, was locked in a tight race with former Secretary of Education Betty Castor. Martinez was running for Democratic Sen. Bob Graham’s seat. Graham retired after three terms as senator.

Sen. Arlen Specter held onto his seat in Pennsylvania against Joseph Hoeffel, winning 52 percent of the vote. Rep. Johnny Isakson won retiring Democratic Sen. Zell Miller’s Georgia seat against Denise Majette.

In Colorado, Attorney General Ken Salazar won against Republican businessman Pete Coors, claiming a formerly Republican seat for the Democratic Party. In Louisiana, David Vitter defeated Chris John.

Though Tuesday’s turnout was predicted to be the largest since World War II, longer lines at the polls did not give Democrats their customary boost..

“The big turnout didn’t have a major effect on the outcome of the Senate races,” said Rogers Smith, chairman of the political science department at the University of Pennsylvania. “There was a big turnout on both sides, so it was less decisive on the side of the Democrats than one would expect.”

Democrats had hoped to entice voters to split their tickets in pro-Bush states, a strategy that did not play out last night. Democratic Senate nominees separated themselves from Kerry, focusing instead on local issues and aligning themselves with more conservative platforms where they could. For instance, Democratic candidate Tony Knowles of Alaska supported opening the Arctic National Wildlife Refuge to oil drilling. The Democratic South Carolina candidate Inez Tenenbaum supported a ban on gay marriage and the invasion of Iraq.

In Kentucky, incumbent Republican Sen. Jim Bunning won against Dan Mongiardo in a narrow victory. Bunning was the favorite early in the race, but a string of gaffes in the past few months put his seat in jeopardy. Bunning accused Dr. Mongiardo, who is dark skinned, of looking like one of Saddam Hussein’s sons. He also refused to speak with reporters and cancelled public appearances, including a debate with Mongiardo last month.

Democrats had hoped for a win in Oklahoma, but former Republican Rep. Tom Coburn took the open seat that had belonged to Don Nickles, a four-term Republican, in this traditionally Republican state. The Democrats put forward Rep. Brad Carson. Coburn was able to pull ahead despite claiming “rampant lesbianism” in the state and favoring the death penalty for doctors who perform abortions.

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