The state remained Mr Kerry's last chance to clinch the presidency on election night. President George Bush held a 130,650-vote lead in Ohio but Mr Kerry had clung to the hope that a sufficient number of uncounted provisional ballots could overturn Mr Bush's majority there.

But given Mr Bush's lead, Mr Kerry would have needed to win between 70% and 80% of the remaining ballots and by yesterday lunchtime he concluded that he was highly unlikely to gain such a margin.

The battle over provisional ballots had promised to be a protracted affair that would have kept the final results in limbo for as long as two weeks. Under Ohio law, the counting of provisional ballots begins 10 days after the election. Provisional ballots are a system designed to protect voters mistakenly dropped from the rolls or otherwise wrongly disqualified. They are most often used when someone has moved and they turn up at a polling place to discover their name is not on the rolls.

Even though they are cast on election day they are set aside, so that the board of elections can check that each voter is in fact eligible. But each county in Ohio has different standards for deciding which vote should be included, which would have prompted fears of an extended legal wrangle between the two sides.

Most of those cast were concentrated in the state's three largest cities, Cleveland, Cincinnati and Columbus where Democrats fared best. The Republicans, recognising the possible importance of the provisional ballots, had taken the issue to the courts before polling ended on Tuesday.

A Republican-sponsored lawsuit demanded better ground rules for evaluating the ballots, and a guarantee that they could watch, alongside Democrats, as state officials prepared the provisional ballots to be counted. Republicans would be looking for as tight a definition of eligibility as possible in order to preserve their lead; Democrats would seek as loose an interpretation as possible in order to narrow their deficit.

The row had briefly placed Ohio at the centre of an electoral storm, promising a deluge of lawyers and journalists into the state capital of Columbus.

Rupert Murdoch's Fox News called the state for Mr Bush just after midnight on Tuesday, but most other news organisations waited for more clarification. "It's Down to Ohio" read the headline of yesterday's Cleveland Plain Dealer.

Over the past few weeks Ohio had been one of the most sought-after prizes in the election, attracting numerous visits from both candidates including a last-minute stop by Mr Bush on election day. Republicans have never won the presidency without winning the state, but in 2000 Mr Gore came close enough to make it extremely competitive this time.

Thanks to an impressive turnout of African-Americans and those in urban areas, Mr Kerry managed to narrow the gap but a huge Republican vote in rural areas, spurred on by a constitutional amendment to ban gay marriage on the ballot, meant it was not enough.

Most of his supporters in Ohio had all but admitted defeat yesterday morning, too crestfallen to clutch at legal straws and not surprised by his decision to concede. Among Ohioans at large views on Mr Kerry's delayed concession were mixed.

Cheryl Mosinski said she voted for Mr Bush, but she didn't blame Mr Kerry for waiting to make a concession speech. "If that were me running, I'd do it," she told Associated Press. Her friend, John Rios disagreed. "Like we told Gore: 'Be a man, take your loss and walk away'," he said.

University student Chris Paul, 31, queued for two hours to vote for Mr Kerry and didn't want that effort to have been in vain. "I don't care how long it really takes," he said. "If I knew the person I voted for would get in, I'd still be waiting in line."