Bush officials were getting ready to pop the corks as the latest results from the key state of Ohio had him clinching the state, taking him over the 270 electoral votes needed for victory.
Bush carried Ohio by a "statistically insurmountable" number of votes and won reelection by a "decisive margin," White House Chief of Staff Andy Card said early on Wednesday.
Card added that Bush had won at least 286 electoral votes and is convinced he has won re-election but will hold off a formal victory declaration to give Democrat John Kerry "time to reflect" on the results.
An official said earlier the White House did not believe the state's disputed provisional ballots would be enough to eliminate Bush's lead in the regular vote count there.
Bush scored a crucial win in Florida in the cliffhanger race for the White House, leaving Democratic Senator John Kerry's hopes for victory hanging on a breakthrough in Ohio.
With 99% of votes counted, two television networks projected that Bush had captured 27 electoral votes of Florida, the state that put him over the top in 2000 and where his brother Jeb is governor.
Kerry won Pennsylvania's 21 electoral votes, but so far neither candidate could break through by winning a state taken by the other party in the bitter 2000 race.
Two TV networks projected Bush
had 27 votes in Florida
Kerry needed a win in Ohio to have a realistic shot at victory, and Bush led there by more than 150,000 votes with 99% of the precincts reporting.
Heavy turnout was reported nationwide and few major voting glitches were recorded in the final act of a presidential campaign marked by deep divisions between Bush and Kerry over the war in Iraq, the fight against terrorism and the economy.
Dire predictions of voter challenges and election chaos mostly did not come true in an election where turnout was expected to sail well past the 105 million Americans who voted in 2000.
Among the remaining battleground states still to be decided at midnight (0500 GMT) are Ohio, Wisconsin, Minnesota, Michigan, Nevada, Iowa, New Hampshire and New Mexico.
Bush's projected win in Florida gives him a giant boost in his bid for re-election, but several other networks refused to call the state for Bush after their experience in 2000. Early projections for Democrat Al Gore that year wound up being wrong.
Voters also are deciding which party holds power in Congress and will vote on governorships in 11 states, with Bush's Republicans favoured to retain control of the Senate and House of Representatives.
John Kerry says he feels he is in a
remarkably strong position
Republicans are considered likely to retain the House and appeared headed to a victory in the Senate.
Republicans picked up Senate seats in North Carolina, Georgia and South Carolina, and rising Democratic star Barack Obama picked up the Illinois seat in an easy win over former presidential candidate Alan Keyes.
A few disputes broke out in key swing states as officials began to count ballots.
A Philadelphia judge blocked the counting of up to 12,000 absentee ballots in the city until he holds a hearing on Wednesday after a complaint brought by the Republican party.
Thousands of people were still in line waiting to vote more than two hours after the polls closed in Ohio, and officials said they would be allowed to stay in line as long as they were there at closing time.
Florida Secretary of State Glenda Hood said it could take until the Thursday deadline to count all of the absentee ballots in the state.
Bush won one-time battlegrounds such as West Virginia, Arizona and Missouri, and Kerry took New Jersey while both candidates scored a series of wins in states where they were favourites.
The counting of 12,000 absentee
ballots in Philadelphia is blocked
Bush and Kerry cast votes in their home states of Texas and Massachusetts respectively, earlier in the day then settled in for a long night of watching and waiting.
Bush, who watched the results in the White House with his family, including his father former president George Bush Snr, said he was confident of victory.
"We're very upbeat, thank you," Bush said. "I believe I will win."
Kerry, watching the results in his hometown of Boston, did not make an appearance before reporters but sent out aides to predict a win. "We are, I think, in a remarkably strong position as we stand here tonight," Kerry adviser Joe Lockhart said.
US oil prices rebounded sharply from early lows on speculation that Bush would win re-election.
Both campaigns said the outcome might not be known quickly and fielded armies of lawyers to challenge close results and prepare for the possibility of another long legal fight like the five-week Florida battle in 2000.