Flood historian John M. Barry says much of the destruction that befell New Orleans came from human error and not an act of God -- and he points the finger at the U.S. Corps of Army Engineers.

An excerpt from the NYT commentary:

We know that Hurricane Katrina made landfall with enormous power, devastating the Gulf Coast, and that the levee on the Industrial Canal in New Orleans was overtopped by a storm surge coming directly from the Gulf of Mexico. When a levee is overtopped, there is basically nothing that can be done. Water pouring over a levee long enough will, in effect, wash part of the levee away. That's what happened on the Industrial Canal, resulting in the flooding of part of the Ninth Ward, along with much of St. Bernard and Plaquemines Parishes.

But most of New Orleans was not flooded by water coming directly from the Gulf. It was flooded from the north and rear by Lake Pontchartrain, when levees failed along the 17th Street and London Avenue drainage canals. Initially, the Corps of Engineers said that the storm was so great that it overtopped these levees also. But after inspecting the levees and reviewing storm data, all three investigating teams agree: Hurricane Katrina hit Lake Pontchartrain with far less strength than it did the Gulf Coast, and the storm surge fell well short of the tops of the levees. In fact, a design or construction flaw caused them to collapse in the face of a force they were designed to hold. In other words, if the levees had performed as they were supposed to, the deaths in New Orleans proper, the scenes in the Superdome and the city's devastation would never have taken place.

Who is responsible? Many accusations, some of them valid, have been hurled at the Orleans Levee Board, a local body. But these accusations are irrelevant. The levee board did not design or build these levees. That was entirely the responsibility of the federal government, through the Corps of Engineers.

Just as a surgeon who improperly sutures an artery is responsible if the suture ruptures and the patient bleeds to death, the federal government is directly responsible for the loss of life and property in most of the city. Although people cannot sue the federal government as they could sue the surgeon, the government still has a moral obligation to repair the damage it caused and to try to make the victims' lives whole again.

But instead of helping, Treasury Secretary John Snow recently told Congress that the administration would not guarantee the city's municipal bonds. So the city government announced the layoff of 3,000 workers. The Catholic archdiocese will let nearly 900 go. The largest employer in the city, Tulane University, may soon have to make similar cuts, and Xavier and Dillard universities, also large employers, are in even more desperate straits. How does one rebuild a city if one destroys its public services and intellectual capital?