Not over yet

President Bush claimed a narrow lead in electoral votes early this morning as a bitterly fought campaign for the White House ended with the incumbent and Senator John F. Kerry awaiting the official outcome in Ohio, where questions about thousands of provisional ballots delayed a final count and threw the entire election into uncertainty.

Invoking the controversy over the presidential vote in Florida four years earlier, Senator John Edwards took the stage in Boston at 2:30 a.m. today vowing to ''fight for every vote."

''It's been a long night, but we've waited four years for this victory. We can wait one more night," Edwards said. ''John Kerry and I made a promise -- that in this election, every vote would count and every vote would be counted. Tonight, we are keeping our word."

Bush advisers had been on the brink of claiming victory after two television networks declared Ohio in his column. The Republican National Committee chairman, Ed Gillespie, appeared triumphantly at 1:26 a.m. to announce that wins in Alaska and Ohio had put Bush within one point of the needed 270 Electoral College votes.

''Hopefully, we'll have one more update, and then another guest speaker," Gillespie said to roars in Washington, as Bush prepared his victory speech.

In the meantime, Kerry officials maintained the outcome in Ohio was far from certain.

''The vote count in Ohio has not been completed," Kerry's campaign manager, Mary Beth Cahill, said in a statement issued at 1:30 a.m. ''There are more than 250,000 remaining votes to be counted. We believe when they are, John Kerry will win Ohio."

With Ohio's 20 electoral votes still up in the air, and another 44 electoral votes still to be determined in Wisconsin, Michigan, Iowa, Nevada and New Mexico, Bush held 249 of the 270 electoral college votes needed to win as of 2:30 a.m today.

Kerry stood at 225 electoral votes, making it slightly more difficult, but not impossible, for him to cross the same finish line -- and raising the possibility the two candidates could reach an even 269-count tie. In the event of a tie, the race would be thrown to the Republican-controlled House of Representatives.

Long considered a Republican must-win, Ohio requires a recount if the candidates are separated by one-quarter of a percentage point or less. The question last night centered around provisional ballots. Across the country, provisional ballots are issued to voters who say they have registered but whose names do not appear on voter rolls at the precinct where they come to cast a ballot. Someone who has moved and failed to update their voter registration with their new address can ask for a provisional ballot.

Ohio redrew its voting district lines after the 2000 Census to reflect population shifts, which led to some confusion as people went to vote at a polling place that no longer covered their neighborhood, another reason for voters to seek a provisional ballot.

Federal law leaves it up to each state to set their own rules for determining under what circumstances provisional votes will be counted toward the official tally.

Ohio, like most states, will honor a provisional ballot only if it has been cast in the precinct where the voter lives. Some other states will honor a provisional ballot as long as the voter cast it somewhere in the same county where they live. Last month Democrats sued Ohio's Republican secretary of state, Kenneth Blackwell, challenging his decision to impose the precinct rule, but a federal appeals court panel upheld Blackwell.

Ohio law also sets an 11-day waiting period before the count of provisional ballots begins.

''This is a very deliberate and conscious process, and I tell everyone to take a deep breath and relax," Blackwell said early this morning on CNN. ''We have a system in place that is time tested. We've been dealing with provisional ballots in Ohio for a decade, and we have a very transparent process where . . . votes are handled in a bipartisan way."

As pf 3:15 a.m., Bush had a lead of 166,072 votes in Ohio, with 51.3 percent over 48.1 percent for Kerry. There were 76,027 provisional ballots, according to the Ohio secretary of state website, but Blackwell said that number could more than double overnight.

An aide to Kerry said that if the number of outstanding ballots in Ohio did not exceed Bush's margin, the candidate would not pursue a recount.

Blackwell said he was not sure how many provisional ballots had been cast in the Buckeye State. Just before 3 a.m., counties had reported more than 76,000 to his office, he said. State officials were unable to say how many absentee ballots had yet to be counted.

Earlier in the day, the first wave of exit polling showed a massive advantage for Kerry, and some websites posted the inconclusive results. But major news outlets and both campaigns were exceptionally cautious, still haunted by the flawed reporting that marred the race in Florida four years earlier, and their wariness proved wise as official exit tallies narrowed the score and ultimately brought Bush into the lead in several of the most important states.

Ralph Nader, the third-party candidate blamed for drawing votes away from Al Gore in 2000, ended the race having made little discernible impact in the 34 states where he was on the ballot.

Both parties held onto their biggest prizes from the last race: Bush took Florida decisively, claiming a mandate in the state he won four years earlier after 36 days of turmoil and a Supreme Court ruling. Kerry triumphed in Pennsylvania, a sharp blow to Bush after 44 presidential trips to the state.

The campaigns marveled at the enormous crowds, with millions of voters pouring into polling stations to take a stand in a race that amounted to a nationwide referendum on Iraq, the war on terrorism and the ailing economy.

Bush captured the Carolinas, although the Democratic vice-presidential candidate, Senator John Edwards, had roots in both. West Virginia, a once-Democratic stronghold that shifted Republican four years ago, fell in line again behind Bush, as did Virginia, a state Kerry had once made a target of heavy advertising. Bush also won Missouri.

Kerry won handily across much of the Northeast, winning statewide in Maine to capture all four of its electoral votes, defying predictions the state would split its votes. In Massachusetts, voters voiced overwhelming disapproval of Bush, two-thirds of them giving a thumbs-down to the president's handling of his job.

But after early exit polls suggested a sizable lead for Kerry in several battlegrounds, the actual returns indicated a much narrower divide, resulting in a long evening of see-saw predictions and baffling tallies.

Hunkered down for an excruciating wait -- with shades of the razor-thin contest four years earlier -- Bush invited a small pool of reporters into the White House to put his upbeat mood on display before balloting stopped on the West Coast.

''I believe I will win, thank you very much," Bush cautiously predicted just before 10 p.m., surrounded by his family after dinner in the White House residence.

The Kerry camp kept vigil in Boston, keeping a wary eye on precinct-by-precinct tallies late into the night as Edwards flew into town for the planned victory celebration at Copley Square.

In Florida, which delivered the presidency to George W. Bush by 537 votes after a contested vote four years ago, problems counting absentee ballots threatened to delay knowledge of final results at first. But the state went to fell in line for Bush around midnight, giving him a solid bloc of 27 electoral votes that put him closer to the 270 needed to win.

Voters on both sides described yesterday's contest as the most consequential election of their lifetimes, an historic turning point whichever direction it went.

''This is the most people I have ever seen in this precinct in my life,"' said Bill DeMora, executive director of the Ohio League of Conservation Voters.

Peter J. Howe and Yvonne Abraham of the Globe staff contributed to this report.