The Governor of Texas, Mr George Bush, and Senator John McCain of Arizona are in a virtual dead-heat in the crucial Republican primary in South Carolina just a day before the election.
The Bush campaign is pouring millions of dollars into TV and radio advertising to try and stave off the McCain challenge. Three weeks ago Mr McCain was trailing Mr Bush in the polls in South Carolina by 20 points, but then came the McCain win in New Hampshire, which showed that Mr Bush was vulnerable in spite of his $73 million war chest.
The latest poll shows Mr Bush leading in South Carolina with 43 per cent of the vote, compared to 40 per cent for Mr McCain.
Mr Bush appears to have consolidated a large lead among Republican voters, where he is ahead of Mr McCain by two to one. But because South Carolina has an "open primary", registered Democrats and Independents can vote in the Republican primary tomorrow and Mr McCain is attracting a majority among those voters.
The third candidate for the Republican nomination, Mr Alan Keyes, has only 4 per cent in the opinion poll but in a close race between the two main rivals, these votes for the TV show host and former ambassador in the Reagan administration could make a vital difference.
Mr Keyes, who is African-American and a Catholic, is receiving a warm reception in conservative South Carolina with his strong moral message, which condemns abortion and challenges people to "vote your conscience".
At a well attended rally in Aiken in the western part of the state on Wednesday night, Mr Bush and Mr Keyes spoke to an enthusiastic Republican audience. Mr Keyes, with his preacher style, was able to inspire his hearers with fervour for the anti-abortion cause. But as they applauded, he told them bluntly that they should not vote for Mr McCain because his stance on abortion was not strong enough.
Mr McCain, who unlike Mr Bush is limited in the amount of money he can spend, is expressing cautious confidence that he can repeat his New Hampshire upset over the Republican frontrunner. He said if he won in South Carolina, he could not be stopped for the Republican nomination. But unlike in New Hampshire, where he beat Mr Bush by 19 per cent, he sees tomorrow's primary as "very close".
The Bush camp is worried about Mr McCain's attraction for independents and Democrats and is using expensive 30-minute "infomercials" on TV and radio to urge Republicans to rally to the Texas governor.
No candidate who has won the Republican nomination in recent years has lost in South Carolina. Both Mr Bush's father in 1988 and Senator Bob Dole in 1996 were given a big boost in South Carolina after setbacks in New Hampshire. Mr Bush jnr is hoping for the same.