What now? One can have an intellectual debate about whether New Orleans ought to be rebuilt. But when House Speaker Dennis Hastert was even caught wondering out loud whether it made sense to rebuild a city six feet below sea level, he was quickly shouted down. In some way, shape, or fashion, New Orleans will be rebuilt, as even Mr. Hastert admitted.

The question is how extensively. Four years after September 11, after all, New Yorkers – who inhabit a far more resilient city than New Orleans – are still debating what to do with the giant hole in the ground that was once the site of the World Trade Center. If anything, the problem of cleaning up after Hurricane Katrina is going to be far more difficult, expensive and traumatizing.

Congress has already voted $10.5 billion for relief and cleanup. But there is talk of a Marshall Plan for the Gulf Coast – $120 billion or so in today’s dollars, after adjusting for inflation. The numbers could go far higher, judging from the pressure on President Bush to make amends for what is widely perceived as the federal government’s failure to respond quickly and effectively enough to the initial catastrophe.

In short, it’s likely to be a far different response than would have occurred after the region’s other great natural disaster, the great flood of 1927, when the mighty Mississippi River rose to flood stage on New Year’s Day – and stayed there for nearly half a year, inundating the entire Mississippi River valley from southern Illinois to Louisiana with one killer wall of water after another. (New Orleans was spared mainly because the water burst through the levees upriver, relieving the pressure.)

Talk about a slow response: As recounted in John M. Barry’s riveting “Rising Tide: The Great Mississippi Flood of 1927 and How It Changed America,” President Coolidge declined repeated requests from governors and others to view the devastation. And talk about a racial divide: Then, as now, the main victims were poor blacks but rather than relocate them compassionately to other parts of the country, the National Guard was used to forcibly contain them in what were called “concentration camps.”

A relief effort led by Herbert Hoover was widely seen as a success, but it depended mainly on volunteers and private contributions through the Red Cross.

Now, however, it’s taken for granted in many quarters that it’s the duty of the federal government to make everybody whole. But as Mr. Hastert was trying to say, some hard questions need to be asked. No doubt Washington will have a big role to play in clearing the debris, rebuilding roads, and helping with other infrastructure. And there will be pressure to establish some sort of victim’s compensation fund, over and above the normal disaster relief.

But the American taxpayer shouldn’t be asked to rebuild New Orleans as it was. That would be an invitation to another disaster. Nor should American taxpayers be asked to create a “model city,” writing blank checks for some Washington planners’ sentimental, utopian view of how the Big Easy ought to look physically.

Instead, federal and state authorities should focus on clearing away the barriers that have made it so difficult for any American city to grow in modern times. That would mean setting aside the regulations, taxes, minimum wages, and other burdens that serve mainly to engorge the federal and state bureaucracies. Make New Orleans a tempting place for entrepreneurial activity, able to compete with Houston and other port cities. Then stand back and let New Orleans spring back – if it will.

The truth is that we cannot know what the new New Orleans will look like. That can only be decided by individuals who see opportunity there. Government’s role is to reduce the barriers to opportunity, not erect a new city.

Mr. Bray is a Detroit News columnist.