A week ago former US President Bill Clinton stood at the lectern of New York's famous Riverside Church and excoriated the Republican leaders for their assault on John Kerry's military record. The former president back from a trip to Ireland, another pit stop on his exhaustive book tour, looked trim and fit, clocking up another euphoric reception among worshippers who seemed to regard him as a deity of sorts.

Today, as Clinton prepares for surgery in the VIP wing of New York's Presbyterian Hospital, his medical diagnosis . . .acute coronary syndrome . . . is giving Democratic political strategists acute political palpitations. While Clinton promised supporters from his hospital bed that he would be back stumping for John Kerry in a matter of days, it is expected that the quadruple bypass surgery and recuperation period will force him off the campaign trial until mid-October.

One Democratic strategist, who spoke on condition of anonymity, said the news was 'a pretty serious blow' to the Kerry campaign. Clinton can always be relied on to energise a crowd, he said, but his real value lies in getting out the African-American vote in cities like Detroit, St Louis and Philadelphia, all cities in swing states that are critical to Kerry's bid for election. "You can't take those states without those cities, and it's going to be tough taking those cities without a high African-American turnout, " he said.

So far Kerry has failed to generate much enthusiasm among black voters, despite exhaustive efforts by grassroots Democratic organisations to register AfricanAmerican voters. In Florida alone, more than 170,000 black voters have registered since March. But Democrats fear without Clinton doing the rounds of black churches and community centres, efforts to energise a critical Democratic demographic may fall short and that black voters, while unlikely to swing towards Bush in significant numbers, may stay home on 2 November.

On Friday evening Clinton's wife, New York Senator Hillary Clinton, made a statement to reporters and bystanders who had gathered outside the hospital thanking Americans for their support. "He's going to be fine and he will be back in fighting form before really very long, after the surgery and period of necessary recovery passes, " she said. Earlier she noted he was beating the family in games of cards and in a political aside added she was grateful she and her husband had good health insurance. "I hope someday everybody will be able to say the same thing, " she added.

According to his office, Clinton checked himself into a local hospital in Westchester on Thursday complaining of mild chest pain and shortness of breath. An initial stress test revealed nothing untoward but a subsequent angiogram revealed he was suffering from acute coronary syndrome, or unstable angina. It is understood that he has several blockages in his arteries and that less invasive procedures such as the insertion of a stent was not an option. A friend of the Clinton's said that contrary to initial reports, Clinton did not suffer a heart attack but is "in imminent danger" of doing so.

Former Clinton strategist Paul Begala said he had been complaining of 'running out of gas early' during his daily jog. Upon checking into the Manhattan hospital he was immediately placed on the blood-thinning drug Plavix. Doctors had intended to operate yesterday but opted to wait until the risk of excessive bleeding during surgery . . . a side effect of Plavix . . . had subsided. The procedure, which involves the grafting of blood vessels from patient to redirect blood around the blockage has a 99% success rate.

A side effect of his sudden illness was its timing for Republicans. All day Friday, Clinton's illness dominated the US news media, eliminating virtually all post-event analysis of the Republican national convention. President Bush spoke to him by telephone and wished him a speedy recovery.