ST. PAUL, Minn. — Republican officials threw away the script for their presidential nominating convention yesterday as Hurricane Gustav bore down on the Gulf Coast and threatened to cast a pall over a week intended to boost Sen. John McCain's campaign for the White House.

With Gustav expected to make landfall sometime today, Republicans scrapped the bulk of their opening-day program, including a scheduled appearance by President Bush, and prepared for a much more sober week of events. McCain used the occasion to portray himself as above partisan politics.

The convention had originally been envisioned as McCain's chance to introduce his little-known running mate, Alaska Gov. Sarah Palin, and define Democratic nominee Barack Obama. But after flying to Jackson, Miss., to receive a briefing from Southern governors on hurricane preparations, McCain called on delegates to take off "our Republican hats and put on our American hats," as he put it in a televised briefing for reporters from St. Louis.

"We must redirect our efforts from the really celebratory event of the nomination of president and vice president of our party to acting as all Americans," McCain said earlier in Jackson. "There's very little doubt that we have to go from a party event to a call to the nation for action — action to help our fellow citizens in this time of tragedy and disaster, action in the form of volunteering, donations, reaching out our hands and our hearts and our wallets to the people who are under such great threat from this great natural disaster."

Convention organizers and McCain advisers watched nervously as Gustav chugged toward land, fearful that the storm could evoke memories of the administration's widely criticized response to Hurricane Katrina three years earlier as Republicans seek to rebrand a party that has been battered under Bush's leadership.

McCain campaign manager Rick Davis told reporters that the seven-hour program scheduled for tonight will be pared down to a bare-bones session of roughly two hours, devoted mainly to meeting the legal requirements involved with opening the convention. He said that there will be no partisan speeches and that officials will assess what to do with the rest of the convention on a "day-to-day" basis until the magnitude of the storm damage becomes clear. He said the GOP will seek to make sure that "nothing we do detracts" from the response efforts in the Gulf states.

MEMORIES OF KATRINA

Even war has not disrupted political conventions in recent years, but the extraordinary decision to alter what had been a meticulously planned coronation of McCain reflected the powerful and lingering political impact of Katrina. Although convention officials refused to discuss any political links between the Bush administration's response to Katrina and their current predicament, some Republicans here were clearly hopeful that by quickly shifting the theme of the convention to aiding relief efforts, they could buttress their efforts to show that a McCain administration would represent a departure from Bush. "It's beginning to creep around the edges that this could be a plus," said one GOP operative who listened in on a campaign conference call yesterday.

The White House canceled tonight's convention speeches by Bush and Vice President Dick Cheney and said the president would be flying to Texas to meet with evacuees and first responders. Bush, who was widely criticized for his initial response to Katrina, visited the Federal Emergency Management Agency's operations center to receive his own hurricane briefing even before Gustav made landfall.

Bush told reporters that he will not travel to Louisiana today "because I do not want my visit to impede in any way the response of our emergency personnel." He said he spoke with governors and New Orleans Mayor Ray Nagin over the weekend "to make sure that they're getting everything they need from the federal government to prepare for what all anticipate will be a difficult situation."

White House officials said that while Bush will not be going to Minnesota, he may address the convention by satellite video. They said that depends on events in the Gulf.

CHANGING FOCUS

The prospect of another natural calamity on the order of Katrina was shaking up the presidential campaign and shifting the focus of the national media. The networks deployed their top anchors from Minnesota to the Gulf region to report on the storm.

McCain and Palin traveled to Mississippi for a firsthand briefing from Republican Gov. Haley Barbour and talked by telephone with the Republican governors of Louisiana, Texas and Alabama. Afterward, McCain said he thought the coordination between federal and local authorities is "dramatically improved" since 2005, adding in St. Louis later that he expects that "the mistakes of Katrina" will not be repeated.

He also responded to gibes from Democrats about the qualifications of Palin, the first-term governor of Alaska, for the vice presidency. "If they want to go down that route, in all candor, she has far, far more experience than Sen. Obama does," McCain said.

Obama, meanwhile, announced that his campaign will mobilize supporters from his enormous e-mail list to send money or enlist as volunteers once the impact of Hurricane Gustav becomes apparent. But the nominee said he will not be traveling to the region because he does not want to disrupt response efforts.

"We can activate an e-mail list of a couple million people who want to give back," Obama said. "I think we can get tons of volunteers to travel down there if it becomes necessary."

MAIN PRIORITY

Briefing reporters in St. Paul at the Xcel Energy Center, where the four-day convention is still scheduled to begin today, GOP officials said all plans for the week are up in the air, save for events that are necessary to nominate McCain. According to party rules, they said, it is required that the convention proceed so that their nominees are placed on the ballot for the Nov. 4 general election.

Campaign advisers made it clear that McCain would very much like to accept his party's nomination in person, though the candidate himself held out the possibility in an interview with NBC News that he might deliver his acceptance speech by satellite. Much depends, they said, on the impact of the storm.

The hurricane was also affecting other activities associated with the convention, such as the prodigious fundraising that is always a sideline to the event. Davis said party officials will be talking with their corporate supporters about directing some of the money raised here to hurricane relief. The party also made available a chartered plane to help delegates from Gulf Coast states return home if they wanted to, and officials will be looking for other ways to boost hurricane relief.

"Our top priority is to assist those who will be affected by Hurricane Gustav," Davis said. "This is not a time for politics or celebration; it is a time for us to come together as Americans and assist the residents of the Gulf states."

Even as Davis refused to speculate on the political fallout from the reordering of the convention schedule, other GOP operatives were hopeful that it would not hurt in the end — and that it might even help. "The first night is kind of a warmup," pollster David Winston said, adding that "the three big speeches" are those of the keynote speaker (former New York Mayor Rudolph W. Giuliani), the vice presidential nominee and the presidential nominee.

"As long as those get full effect, then everything's fine," he said.

Barnes reported from Jackson, Miss. Washington Post staff writers Michael D. Shear and Shailagh Murray and www.washingtonpost.com staff writer Ben Pershing contributed to this report.