John McCain will seek to portray himself this week as a transformational Republican acceptable to independent voters and even disaffected Hillary Clinton supporters when his nominating convention opens in Minnesota on Monday, with his surprise choice of the little-known Alaskan governor Sarah Palin as the first step.

With Mrs Palin’s choice guaranteeing a significant increase in interest for the convention in the Minnesota capital St Paul, there will be four days of speeches and events in which Barack Obama will be relentlessly attacked and from where the Republican presidential candidate will try to emerge as a conservative maverick, but independent from President Bush.

This weekend, as he embarks on a tour of three major battleground states with Mrs Palin — Ohio, Pennsylvania and Michigan — Mr McCain has two immediate concerns: the appearance on the opening night of President Bush and Vice-President Dick Cheney, and a hurricane approaching the Gulf Coast — on the third anniversary of the Katrina debacle.

There was even talk among Mr McCain’s aides of possibly postponing the opening of the convention if Hurricane Gustav heads toward Louisiana, with residents of New Orleans, a city still devastated by Katrina, already making preparations to flee.

Republican strategists are aware that a party celebration in Minnesota as a hurricane hits the Gulf Coast — particularly after the disastrous response to Katrina — would be politically untenable.

“The Republicans can’t seem to catch a break when it comes to August and when it comes to the weather,” said Karl Rove, Mr Bush’s former chief adviser, who was in the White House when Katrina struck. Mr Bush and Mr Cheney — and the First Lady, Laura Bush — will speak on Monday, but will leave St Paul as soon as they have finished.

Although two thirds of Republicans still like their President, Mr Bush has an approval rating of less than 30 per cent nationally, with Mr Cheney’s rating even lower. Mr Obama and his fellow Democrats spent their convention in Denver linking Mr McCain, 72, to Mr Bush at every opportunity.

The theme of the convention — where Mr McCain’s five-and-a-half years as a Vietnamese prisoner of war will feature strongly — is “Country First”. Mr Obama will be portrayed relentlessly as a feckless, inexperienced liberal. The keynote speaker on Tuesday will be Rudy Giuliani, the former Mayor of New York, a particularly good practitioner of hard-edged, verbal assault.

However, so tainted is the Republican brand that six senators and several congressmen who are locked in tight re-election campaigns against moderate Democrats are refusing to attend the convention.

There will be no shortage of country and western music — indeed, there will be little other music on offer — although the convention will kick off on Monday with the Beach Boys.

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