Al Gore made his controversial decision in the wee hours of that November morning in 2000, even as eager U.S. Republicans prepared to celebrate their party's return to the White House after eight years.
The Democratic candidate, who had surprised supporters by being unable to turn peace and prosperity into a clear victory over George W. Bush, was about to throw a spanner into the Republican works.
He had phoned Mr. Bush to concede earlier in the evening, hours after the television networks said that his opponent had won Florida. But then he reconsidered as the situation in the crucial battleground state fluctuated.
The then-vice president placed a call and asked to be put through to Mr. Bush. He had a simple message for the Texas governor, but one which set off weeks of legal wrangling that threatened constitutional crisis in America.
"I need to withdraw my concession until the situation is clear," Mr. Gore said, leaving Mr. Bush momentarily speechless.
Another Gore aide quoted him saying: "If, in fact, I lose in Florida, I will immediately concede. But it's not in any way clear I have lost and until it is clear I can't concede."
"Do what you have to do," Mr. Bush said. Mr. Gore hung up.
It was another twist to an extremely tough election that forced both candidates to head off challenges from their own party before even having a chance to confront each other.
Although Mr. Gore, who served eight years as vice-president to Bill Clinton, was the obvious early choice for the Democratic nomination, New Jersey Senator and former pro basketball player Bill Bradley mounted a strong challenge. On the other side of the aisle, Mr. Bush had to fight back the appeal of Arizona Senator John McCain, a wounded veteran who had been held captive by the North Vietnamese.
Mr. Gore had the initial advantage when the candidates finally went head-to-head, with polls showing an extremely close race amid early stumbles by Mr. Bush. The Texan regained his momentum during the debates, though, aided by his efforts to lower expectations. He was considered to have bested Mr. Gore.
Eager to assume the presidency, Mr. Gore set off a series of legal battles. The fighting was so intense commentators warned that it threatened the legitimacy of the U.S. electoral system and emerging democracies around the world offered snide comments. Through it all he insisted that he was protecting the democratic process itself, and that he would concede immediately if the tally went against him.
At the heart of Mr. Gore's complaint were the problems caused by ballot-machines that did not always reflect voters' intentions. In some cases the voting card was not properly punched, leaving "dimpled" or "hanging" chads. A much-criticized ballot design in Palm Beach County may have confused some, leading to right-winger Pat Buchanan racking up substantial support in spite of the large Jewish-American population in the area.
The tension grew as the candidates battled over the need for recounts in disputed districts.
Nearly a week after the election, on Nov. 14, 2000, the Florida result was officially certified by the Republican-dominated state house, giving it to Mr. Bush. But a Florida judge ruled the same day that recounts could be considered later. At that point Mr. Bush led by some 300 votes.
Six days later the Florida Supreme Court heard arguments and, after deliberating only one day, ruled that recounts must be added to the final state tally by 5 p.m. on Nov 26. On that day state election officials declared Mr. Bush the winner a margin of 537 votes
"Now that the votes have been counted, it's time for the votes to count," Mr. Bush said.
The Gore camp immediately vowed to fight the results.
In a pre-emptive move, days before his victory was official, Mr. Bush had petitioned the U.S. Supreme Court to overrule the Florida decision. The highest U.S. court agreed to hear his challenge. On Dec. 12, 2000, Supreme Court justices overturned the Florida decision.
It was not until Dec. 18 that the Republicans could finally have their victory party. On that day, traditionally the first Monday after the second Wednesday in the month following the vote, the final stage of the election was completed.
He garnered 271 of their votes, one more than he needed to become president. Florida put him over the top and helped make him the United States' 43rd president.
(Eleven months later a news consortium commissioned a study from the University of Chicago's National Opinion Research Center, seeking to examine the disputed ballots and sort out the voters' intentions. The result was so close and so murky that it was still unclear who had won.)