President Bush and John Kerry during the third and final presidential debate in Tempe, Ariz., Wednesday, Oct. 13, 2004.
Polls are closed in more than 40 states but the race for the White House is still up in the air Tuesday night as the Big Three battleground states of Florida, Ohio and Pennsylvania remain too close to project a winner.

Together, the three states combine for 68 electoral votes, one-fourth of the coveted total of 270.

As of 10:30 p.m. ET, CBS News estimates Mr. Bush has 196 electoral votes versus 112 for Kerry. In the popular vote, Mr. Bush was leading Kerry 25,808,784 to 24,024,418. Independent candidate Ralph Nader had 171,859 votes.

So far, the race was mirroring the 2000 election, with Mr. Bush winning all the states he carried four years ago, and Kerry winning all the states former Vice President Al Gore captured.

Mr. Bush swept the South with wins in Texas, Arkansas, Louisiana, Virginia, South Carolina, North Carolina, Alabama, Mississippi, Tennessee, Georgia and Kentucky. He also did well in the West and Midwest, capturing Missouri, Indiana, Kansas, Nebraska, Wyoming, South Dakota, North Dakota, Oklahoma, Utah and Montana.

Kerry dominated the East and Northeast with victories in New York, New Jersey, Rhode Island, Connecticut, Vermont, Delaware, Maryland and the District of Columbia, as well as his home state of Massachusetts. He also carried the electoral vote-rich Midwest state of Illinois.

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There was insufficient information to project a winner in several states including Nevada, Iowa, Arizona, Colorado, Michigan, Minnesota, New Mexico, Wisconsin and New Hampshire.

Kerry won the statewide vote in Maine, worth three electoral votes. Maine's northernmost congressional district, worth a single vote, was too close to call.

So was the Senate, where Republicans held a 51-48 advantage with one Democratic-leaning independent. Democrat Barack Obama of Illinois became the third black U.S. senator since Reconstruction.

Only nine of 34 Senate races on the ballot appeared competitive, including Senate Democratic Leader Tom Daschle's fight for re-election in South Dakota.

CBS News estimates the House of Representatives, where all 435 members were up for election, will remain under Republican control.

Eleven gubernatorial contests were also being decided Tuesday, along with 5,800 legislative seats in 44 states.

Among the notable ballot measures was one in California to devote $3 billion for stem cell research. Several states had propositions that would ban same sex marriage.

But all eyes were focused on Kerry's bid to make Mr. Bush the first president voted out of office at a time of war.

"I've given it my all," the president said after voting at a Crawford, Texas, firehouse.

Kerry, a four-term Massachusetts senator, got teary-eyed as he thanked his staff for a campaign's worth of work. "We made the case for change," he said after voting at the Massachusetts Statehouse.

Early results from exit voting suggest that young people are playing a greater role in this year's presidential race than four years earlier. In 2000, 17 percent of voters nationwide were between the ages of 18 and 29. They broke nearly evenly between the major party candidates, with 48 percent supporting Gore and 46 percent supporting Mr. Bush.

This election the impact appears to be much more striking. Although they have not turned out in greater numbers nationally, they are leaning heavily toward Kerry, giving him a double-digit lead over the president among this age group.

The results are even more dramatic in several key battleground states. Roughly one in five voters in Ohio is under 30, supporting Kerry by roughly 20 percent over Mr. Bush. About one in six voters in Florida are between 18 and 29, leaning toward Kerry by about twenty percentage points. In Pennsylvania, more than 20 percent of voters are under 30, and they break toward Kerry by nearly twenty-five percentage points.

Both parties made an effort to get voters to the polls who did not participate in the 2000 election. Current exit poll findings suggest that this effort was somewhat successful. About one out of every six voters this year report not having voted in the 2000 presidential election. While both parties hoped a targeted effort could boost their prospects this election cycle, it appears that these voters are breaking for Kerry by roughly a 20-point margin.

CBS News National Exit Poll results are based on interviews with 11,027 voters. The sampling error is plus or minus 1 point. Exit Polls from specific states are based on interviews with at least 1930 voters, and could have a sampling error of as much as plus or minus 2 points.

With polls deadlocked and interest in the race exceptionally high, voter turnout was heavy. Some polls projected Election Day 2004 may see the largest proportion of eligible people voting in a generation.

There were some controversies and legal disputes over close races in some key swing states. In Ohio, a a federal appeals court approved a GOP plan to station observers in polling places. In Florida, the counting of absentee ballots began, but thousands were delayed going out.

Even as voters streamed to polling places to make their picks, the candidates kept campaigning.

"This election is in the hands of the people, and I feel very comfortable about that," Mr. Bush said near his Texas ranch.

On his way back to Washington, he stopped in Columbus, Ohio, and made a few calls from a phone bank. "I promise you, it's me," he told one doubter.

Kerry voted along with his daughters in Boston. "I don't think anybody can anticipate what it's like to see your name on the ballot for president," he said. "It's very special. It's exciting." His wife cast her ballot earlier in Pennsylvania.

Sen. John Edwards, who had cast his North Carolina ballot in early voting, stopped by polling places in Florida and said, "We believe the system's going to work the way it's supposed to." Vice President Dick Cheney voted near his home in Wyoming and said, "When you start a day like this in Jackson Hole, it's going to be a good day."

Long lines were reported at precincts from Florida and North Carolina to West Virginia and Michigan.

"We even had people waiting in line before we opened at 6:30 a.m.," said Wayne County Clerk Robert Pasley in Wayne, W.Va. "In some places, there was more than a dozen people waiting, and that's heavy."

The prospect of unprecedented legal challenges hung over Election Day, each side sending thousands of lawyers into motion to monitor the flood of newly registered voters and mount hair-trigger challenges against any sign of irregularity.

"My hope of course is that this election ends tonight," Mr. Bush told reporters, referring to the expected legal challenges in some districts.

Scattered technical problems were reported around the country. One polling location in Mauldin, S.C., was forced to switch to paper ballots because of equipment troubles.

In Volusia County, Fla., a memory card in an optical-scan voting machine failed Monday at an early voting site and didn't count 13,000 ballots. Officials planned to feed and count those ballots Tuesday.

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