Even before it hits the Gulf Coast, Hurricane Gustav is tearing up plans for the Republican National Convention with President Bush and Vice President Dick Cheney cancelling their prime time speeches today.

Other speakers have been told to "refrain from political rhetoric" as organisers announced a severely truncated convention that meets this afternoon for a brief business-only session, cut from seven hours to just two and a half.

John McCain, who still expects to be anointed as Republican nominee on Thursday, said: “I hope and pray we will be able to resume some of our normal operations as soon as possible, but that, frankly, is in the hands of God.”

After flying to Mississippi with his wife, Cindy, and running mate Sarah Palin, he said: "This is a time when we have to do away with our party politics and we have to act as Americans." His campaign has chartered jets to fly delegates back to their hurricane-threatened Gulf Coast states.

Mr McCain had earlier told Fox News: “It just wouldn’t be appropriate to have a festive occasion while a near-tragedy or a terrible challenge is presented in the form of a natural disaster.”

Convention organisers have set up a committee to evaluate Gustav’s impact on the event. Further schedules will be decided on a day-to-day basis. Rick Davis, Mr McCain's campaign manager, said: "We are working with the delegations, financial people, finance committees, many other concerned individuals to do what we can to raise money for various charities that operate in the Gulf Coast region."

Mr Bush, after touring the Federal Emergency Management Agency, announced he would travel to Texas tomorrow to review storm preparations rather than attend the convention. He told those fleeing from the path of the hurricane that they should "know that the American people stand with you and that we’ll face this emergency together".

The President was heavily criticised for his slow, even inept, response to Hurricane Katrina in 2005. He first surveyed the damage by flying over the area on Air Force One and later praised Michael Brown, then Fema’s head — a political ally accused of being utterly unqualified for the post — for doing a “heck of a job”.

Even before Gustav some strategists had been dreading the arrival of Mr Bush and Mr Cheney in St Paul, fearing it would provide Barack Obama with fresh material to tie Mr McCain to an unpopular administration.

But showing sensitivity to a new disaster could help remove the taint of uncaring incompetence that has stuck to the Republicans ever since. Mr McCain has previously gone out of his way to underline how he would have handled Katrina differently.

“Never again, never again will a disaster of this nature be handled in the terrible and disgraceful way that it was handled,” he said this year on a tour of the still-devastated Lower Ninth Ward in New Orleans. Yesterday, he said: "I have every expectation that we will not see the mistakes of Katrina repeated.”

It has emerged that a series of prominent supporters of Mr McCain, including Governors Bobby Jindal of Louisiana and Charlie Crist of Florida and Hayley Barbour of Mississippi are likely to miss the convention because of the storms.

Mr Obama has promised to steer clear of the Gulf Coast so that he does not impede relief work. The Democratic nominee promised he will ask his huge network of donors and activists to help hurricane victims.

“I think we can get tons of volunteers to travel down there, if it becomes necessary,” he said after attending church in Lima, Ohio.

But he was unable to prevent some off-message gloating from Democratic colleagues such as former party chairman Don Fowler who said the timing of the hurricane just before the convention "demonstrates that God's on our side".

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