As Governor George Bush holds on to his narrow lead in the national polls, the Gore campaign is homing in on Florida as the state which could cost the Republican candidate the presidency.
Vice-President Al Gore and his running mate, Senator Joseph Lieberman, campaigned across Florida yesterday, denouncing Mr Bush's plans for social security as a threat to the large population living on pensions.
"If we win it here, we'll win it everywhere," Mr Lieberman predicted on NBC's Today.
Mr Gore hammered away at social security issues. He told a meeting of elderly citizens at Kissammee: "I don't want to gamble with the programme that is the cornerstone of retirement security for millions of Americans."
The Bush campaign was also in hot pursuit of Florida's support, with Mr Bush's father, former President George Bush, his mother Barbara and his brother Jeb, the Governor of the state, begging voters to reject the strong Gore challenge in what used to be a strongly Republican state. Mr Bush's running mate, Mr Dick Cheney, former secretary of defence, and Gen Norman Schwarzkopf, "Stormin' Norman" of Gulf War fame, were also on the campaign trail in a state where there are many veterans of the armed forces.
Governor Jeb Bush insisted his brother "is going to carry Florida". He accused Mr Gore of using false charges about his brother's social security reform plan "as a club to scare people across the country".
The Gore camp is convinced that if Mr Bush does not win Florida, with its 25 electoral college votes, he cannot win the election given that Mr Gore is certain to win New York with 33 electoral votes and fairly confident of California with 54 votes. So with just three states, Mr Gore would have 112 of the 270 electoral votes he needs to win the White House.
Mr Bush is certain to win Texas with 32 electoral votes but the Rocky Mountain, western and southern states which he will also win have only small populations and few electoral votes.
Under the 200-year-old US Constitution, voters in a presidential election are choosing an electoral college with representatives from each state who will later formally elect the President. The candidate who wins the most votes in each state wins all the electoral votes - Maine and Nebraska split them - so that Mr Bush could lose Florida by a handful of votes next Tuesday but under the winner takes all system, Mr Gore would get all the 25 electoral college votes.
The Reform Party candidate, Mr Ross Perot, won 19 per cent of the popular vote in 1992 but no electoral votes.
In theory, Mr Bush could be defeated in Florida and make up for this loss by winning big in the Mid-West, but these battleground states are being fiercely contested. Hence, Florida is a vital state for Mr Bush.
A Reuters estimate of the electoral college votes in the last week of the campaign has Mr Bush with 217 to Mr Gore's 207 and 114 too close to call.
Some political analysts are beginning to think the unthinkable, namely that Mr Bush could win the popular vote but Mr Gore would win the electoral college and therefore the presidency. This has not happened since the 19th century but in 1960, John F. Kennedy easily defeated Richard Nixon in the electoral college but less than one per cent separated them in the popular vote.