President Bush moved to the brink of securing his bid for reelection early this morning, winning the prized battleground of Florida and holding what appeared to be an insurmountable lead over Sen. John F. Kerry in Ohio. But the Massachusetts senator considered continuing his battle to win the White House with a fight over provisional ballots in the Buckeye State.

With reports of pandemonium inside the campaign, Kerry's running mate, Sen. John Edwards (N.C.), appeared at Boston's Copley Plaza at 2:30 a.m. vowing to continue the fight. "John Kerry and I made a promise to the American people that in this election every vote would count and every vote would be counted. Tonight we are keeping our word and we will fight for every vote. You deserve no less."

Bush had planned to speak to supporters once the results were clear but held off once Edwards made his announcement, with aides expressing irritation at the Democrats. At the time Edwards spoke, Bush, who lost the popular vote four years ago, was leading Kerry by more than 3.7 million votes nationally -- 51 percent to 48 percent. He had 254 electoral votes to Kerry's 242. To win the presidency, 270 votes are needed.

As the presidential election headed toward potential legal wrangling, Republicans expanded their majority in the Senate and appeared likely to do the same in the House. In Senate races, the GOP picked up open Democratic seats in Georgia, Louisiana, North Carolina and South Carolina, while Democrats captured open Republican seats in Illinois and Colorado. In the most closely watched race, Senate Democratic leader Thomas A. Daschle was trailing former House member John Thune (R) in South Dakota.

In Ohio, with nearly all the votes counted, Bush led 51 to 49 percent and a margin of 140,000 votes. Ohio Secretary of State J. Kenneth Blackwell (R) estimated that there will be 175,000 provisional ballots by the time the counties finish their tabulations. Democrats said there could be as many as 250,000.

The state's Republican senators, George V. Voinovich and Mike DeWine, issued a statement calling on Kerry to concede the state, arguing that he could not make up his deficit with the provisional ballots. "Senator Kerry should concede defeat and spare the country the turmoil of another drawn-out election," the statement said.

Kerry advisers said there would be no decision until later today, but some Kerry sources indicated that he is not likely to continue his candidacy if the odds look hopeless.

Michigan tipped to Kerry early this morning and Nevada went to Bush. With Ohio's 20 electoral votes, Nevada was enough to give him the presidency.

As the Kerry campaign closed down for the night, three other states remained in play: Wisconsin, Iowa and New Mexico. Bush led in New Mexico by less than 2,000 votes and in Iowa by about 11,000 votes. Kerry led in Wisconsin by about 20,000 votes. Recount provisions varied in some of the remaining closely contested states.

With the election shaped by the fight against terrorism and the country deeply divided over the war in Iraq and the economy, energized voters poured out in extraordinary numbers nationwide, prodded by the two campaigns, which worked overtime to get their supporters to the polls.

After a night of agonizing counting and mood changes inside the campaigns, the 2004 election appeared to be a virtual rerun of the hard-fought contest that gave Bush the presidency four years ago. The Kerry campaign rested its hopes on provisional ballots -- those cast by voters who were not on registrars' rolls yesterday -- and other ballots still uncounted in Ohio, which Republicans said still would not be enough to carry the state.

Polling places in some battlegrounds, including Ohio, stayed open long after their scheduled closings as officials struggled to handle a surge in turnout that some experts said could match the most recent high-water mark, set in 1992 -- and perhaps exceed it. Despite threats of legal challenges and other disruptions, voting generally appeared to go smoothly in most states.

Early exit polls appeared to give Kerry a small advantage, but as the night wore on and the actual vote tallies mounted, Democratic exuberance gave way to tense hours of counting and increasing pessimism. When the president fought off Kerry's challenge in Florida, the state that produced the bitter 36-day recount battle four years ago, he significantly complicated Kerry's route to the 270 electoral votes needed to win.

The pattern of the returns proved to be a virtual rerun of the 2000 election, with many of the states that created such drama in that contest once again keeping the candidates and the American people on edge as they watched returns roll in. By early this morning, only one state had switched sides, with Kerry taking back New Hampshire from the Republicans.

Otherwise, there were no surprises as the states began to report. Bush methodically secured his base in the South and border states, capturing his home state of Texas as well as Virginia, Georgia, Alabama, South Carolina, Mississippi, Louisiana, Tennessee, Missouri and Kentucky. He won Indiana and West Virginia, which was a Democratic bastion until Bush won it four years ago. In the Great Plains and Rocky Mountains, he rolled to a series of victories.

Kerry began a march across the country's northern tier, beginning in New England with victories in his home state of Massachusetts as well as in Connecticut, Rhode Island and Vermont. To that he added Maryland, the District, and several big prizes: California, New York, Pennsylvania, New Jersey, which the Bush campaign looked at briefly, and Illinois, one of the few states in the Midwest that were not closely contested.

But the two sides were focused on two of the big states where the candidates had spent most of their time and money, Florida and Ohio, and on half a dozen other states that could tip the balance: Wisconsin, Minnesota, Michigan, Iowa, New Hampshire and New Mexico. As the counts came in, the campaigns struggled to examine the data for clues to the outcome.

Early in the day, based on exit polls by the National Election Pool, Bush appeared to be in danger of losing the election and joining his father in being swept out of office after a single term. George H.W. Bush lost his reelection bid in 1992 to Bill Clinton, and the current president systematically sought to avoid the mistakes he believed cost his father that election. But the fact that he did not significantly expand his coalition over that of four years ago put him in another tough fight this year.

After the 2000 election, the country united around Bush's presidency when terrorists attacked on Sept. 11, 2001. But that unity faded and, after the U.S.-led invasion of Iraq, the nation became polarized. Yesterday's electorate appeared as divided as it was four years ago.

Bush and Kerry monitored the voting last night from their respective bases of operation in Washington and Massachusetts. Bush voted in Texas in the morning, stopped in Columbus, Ohio, in a show of support for his campaign workers there, and returned to Washington in the afternoon.

Bush spent the evening at the White House residence, surrounded by family and a few close advisers. Kerry began his day in La Crosse, Wis. He then flew to Boston to vote and returned to his Beacon Hill home. He spent four hours doing 38 satellite interviews with local television stations, trying to spur his supporters to vote. Edwards joined in that effort.

Three issues dominated the campaign and shaped yesterday's vote: terrorism, the war in Iraq and the national economy. Kerry overwhelmingly won among those who said Iraq and the economy were the most important issues to them, while Bush won by a landslide among those who cited terrorism. Beyond those issues, a fifth of yesterday's voters said moral values influenced their choice, and Bush won them by 4 to 1.

No barometer has been watched more closely throughout the campaign than the president's approval rating, often considered an indicator of the chance of winning reelection. Ronald Reagan and Clinton were reelected with approval ratings in the mid-fifties, while George H.W. Bush and Jimmy Carter lost when their approval ratings plunged to 40 percent or below.

Yesterday, according to exit polls, Bush's approval rating stood at 51 percent, still occupying a political netherworld that provided evidence of how competitive the race remained to the end.

Outside events shaped the campaign far more than the candidates' strategists did, helping to negate some of the normal advantages enjoyed by an incumbent seeking reelection. The campaigns battled over whether the economy is in clear recovery or is still struggling. At several crucial turns, job figures put Bush on the defensive, and voters gave the economy negative marks yesterday but split over whom they trust more to fix things.

Iraq proved even more troubling for Bush. As the general election campaign opened in the spring, a succession of events put him back on his heels, such as evidence that the insurgency was stronger than the United States had estimated, mounting casualties and then the prison abuse scandal. Bush struggled to explain his policy. In the final weeks, Iraq took center stage again, with stories of kidnappings, beheadings, criticism of the president's policies and more casualties. Yesterday, voters split almost evenly over whether it was right or wrong to go to war, with a majority saying things there are not going well.

The 2004 campaign will rank as the longest and costliest in American history, a battle that began the day after Kerry wrapped up the Democratic nomination contest on March 3 and continued through the trench warfare of turning out voters until the polls closed last night. At times, it was also one of the most negative, marked by angry anti-Bush energy that first surfaced during the Democratic primaries and by relentless criticism of Kerry by the Bush campaign.

When the Democratic nomination fight began in early 2003, Bush was in a strong position, coming off a historic midterm election victory by his party that was fueled in part by the unity engendered by his actions after the Sept. 11 attacks. He enjoyed an approval rating of 60 percent or better, but over the next months the president took a huge gamble by beginning the war in Iraq. The success of the initial invasion drove his popularity even higher, but over time the war became the most divisive decision of his presidency.

Bush's campaign wasted no time in going after Kerry, pummeling him as a politician who had been on both sides of virtually every major issue of the past two decades. Bush began the attack with a touch of humor, but the Bush campaign's advertising and Vice President Cheney's rhetoric carried a much sharper edge that soon began to cut into Kerry profile.

The challenger took a narrow lead heading into his convention in Boston in late July. There, over four nights of speeches and celebration, the campaign highlighted the senator's service in Vietnam, hoping once and for all to convince voters that he had the credentials to be commander in chief. He emerged temporarily stronger -- until the Bush campaign and its allies struck back.

August quickly became an ordeal for Kerry. A group called Swift Boat Veterans for Truth aired television ads questioning his combat record in Vietnam, and with a minimal amount of money it took the entire presidential campaign back almost four decades into a debate about that divisive war. Bush could not escape the fracas either, with new questions raised about his service during the war, but it was Kerry who bore the brunt of it.

Republicans gathered in New York at the end of August for their convention and skillfully reconnected Bush with the events surrounding Sept. 11, 2001, the high point of his presidency and a powerfully emotional hinge point for the country. The Republicans also used their convention, in a way the Democrats did not, to attack the opposition.

Bush emerged from his convention with a lead in the polls and pressed his advantage throughout September. Kerry went through another staff shake-up, recruiting several veterans of the Clinton administration and realigning responsibilities. He also set the stage for a fresh debate about Bush's policies in Iraq, reengaging on an issue that had turned into one of Bush's biggest problems.

The debates gave Kerry another opening, and he took advantage. In the first debate, Bush looked and occasionally sounded impatient and angry, and even his supporters knew the challenger came out as the winner. Through two more debates, Kerry more than held his own, providing a morale boost to his campaign and, more important, to the legions of Democrats who had watched August and September with growing alarm.

The final weeks generated some of the toughest rhetoric of the campaign and a back-to-basics strategy from both candidates. Fighting more bad news from Iraq, Bush continued to question Kerry's fitness to lead the country in the war on terrorism. Kerry seized on every headline he could find, including the lack of flu vaccine, to indifferent job numbers and missing high explosives in Iraq to argue that Bush's presidency has been a failure. Kerry called for a fresh start; Bush warned Americans not to take the risk.

President Bush makes an Election Day visit to battleground Ohio.John F. Kerry leaves the statehouse in Boston after casting his vote.President Bush talks to reporters after he and first lady Laura Bush voted at the fire station in Crawford, Tex.Sen. John F. Kerry casts his ballot at the statehouse in Boston. He spent four hours doing 38 satellite interviews.Shane Onufrock of Rockville is among the Republicans who gathered at the Ronald Reagan Building in the District to watch returns.John Scanton of Boston, sporting a balloon "hat," watches returns at Sen. John F. Kerry's election headquarters in Boston.Democratic vice presidential nominee John Edwards tells a crowd in Boston that he and Kerry plan to continue their fight.