But Mr. Williams added: "You cannot just blame the president, or any one person. Everyone is partly to blame. It's the whole system."

It was the combination of specific and systemic failures that many of those interviewed -- experts and ordinary people alike -- echoed.

Andrew Young, the former civil rights worker and mayor of Atlanta who was Jimmy Carter's ambassador to the United Nations, was born in New Orleans 73 years ago, walked on its levees as a boy and "was always assured by my father that the Army Corps of Engineers had done a masterful job." But, Mr. Young said, "they've been neglected for the last 20 years," along with other pillars of the nation's infrastructure, human and physical.

"I was surprised and not surprised," he said of the failures and suffering of this week.

"It's not just a lack of preparedness. I think the easy answer is to say that these are poor people and black people and so the government doesn't give a damn," he said. "That's O.K., and there might be some truth to that. But I think we've got to see this as a serious problem of the long-term neglect of an environmental system on which our nation depends. All the grain that's grown in Iowa and Illinois, and the huge industrial output of the Midwest has to come down the Mississippi River, and there has to be a port to handle it, to keep a functioning economy in the United States of America."

Mr. Riley, the Charleston mayor, whose Police Department on Monday sent 55 officers to help keep order in Gulfport, Miss., said he had long advocated creating a special military entity -- perhaps under the Corps of Engineers -- that could respond immediately to disasters.

"It's not the police function," he said. "It's that it's an entity that knows how to quickly restore infrastructure and the essentials of order." He said his own experience with the Federal Emergency Management Agency during Hurricane Hugo in 1989, when he had the National Guard on standby and then requested Army troops and marines, had convinced him that civilian bureaucracy was sometimes too caught up in the niceties.

"With the eye of Hugo over my City Hall, literally, I said to a FEMA official, 'What's the main bit of advice you can give me?' and he said, 'You need to make sure you're accounting for all your expenses," Mayor Riley recalled. "The tragedy of these things is the unnecessary pain in those early days, the complete destruction of normalcy."