Hillary Clinton is promising a last-ditch confrontation with Barack Obama in tomorrow night’s television debate, their final head-to-head appearance before next week’s crunch elections in Ohio and Texas.

She has accused her rival, who has replaced her as the front-runner for the Democratic presidential nomination, of deliberately distorting her positions on trade deals and healthcare in mailshots to voters.

On Saturday she waved two such leaflets from his campaign, saying “shame on you, Barack Obama” as she contrasted his high-minded rhetoric with his use of “tactics that are right out of Karl Rove’s playbook”. Her reference to Mr Rove, the strategist who masterminded President Bush’s twin election victories, is particularly incendiary for Democrats. She said that Mr Obama was giving “aid and comfort to the very special interests and their allies in the Republican Party”.

Before tomorrow’s TV showdown in Cleveland, Mrs Clinton said: “Meet me in Ohio. Let’s have a debate about your tactics in this campaign.” Her anger was in sharp contrast to the grace she showed towards Mr Obama last week in Texas. He has now clocked up 11 consecutive victories over her.

Yesterday Ralph Nader announced an independent bid for the presidency, his sixth in consecutive elections. He is remembered for having won 2.7 per cent of the vote in 2000, arguably helping Mr Bush to beat Al Gore by a narrow margin. But most analysts expect him to have little impact this year, possibly even less than in 2004 when he achieved only 0.3 per cent support.

Instead, the weekend clashes showed that another ghost from the past was more likely to haunt the race. Mrs Clinton’s deep sensitivity on the issue of trade is because it was her husband’s Administration that signed the North American Free Trade Agreement (Nafta) 15 years ago. It is a deal that has since been blamed for the rapid decline in US manufacturing industry in rust-belt states such as Ohio, which has lost 200,000 manufacturing jobs since 2000. Polls suggest that it is opposed by almost three quarters of the state’s Democrats, especially blue-collar voters upon whom Mrs Clinton is counting.

Mr Obama’s leaflet quotes a 2006 Newsday article suggesting that she believed the agreement had been a boon to the economy. The newspaper has since accepted that she never uttered the word. But Mr Obama is standing by his allegation, pointing out that she had referred to it in her autobiography as one of the victories of the Clinton White House. Speaking in Lorain, Ohio, he said: “Senator Clinton also said I’m wrong to point out that she once supported Nafta. But she was saying great things about Nafta until she started running for president.”He questioned why Mrs Clinton was upset about mailshots that have been circulating for weeks, saying: “It makes me think there was something tactical about her getting so exercised.” But she claims that the basis of the deal had been negotiated before Mr Clinton became President. Ted Strickland — Ohio’s Governor, who has endorsed her — was among those seeking to change the historical record. “Bill Clinton has told me personally that Hillary was not in favour of Nafta when it passed,” he said.

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