Within hours of Hurricane Gustav making landfall in Louisiana, federal officials were holding news conferences congratulating themselves on having successfully avoided another Katrina-style disaster. The theme coming out of all of these proclamations was that the federal government had learned from Katrina and that, through their diligence, a major catastrophe had been averted.

The real lesson that the people on the ground learned from Katrina — and what accounts for the successful preparation for Gustav — is that when the forces of nature come calling, you cannot rely on statements from officials to make your plans.

With the memory of Katrina fresh in their minds, the residents of the Louisiana and Mississippi coasts began evacuating as early as Thursday, almost four days before Gustav made landfall. Necessities, either for the road trip or for hunkering down at home, were in ready supply in local stores due to the diligence of retailers, who brought in trucks of supplies to serve their customers — not to fill a government purchase order.

Wal-Mart’s emergency operations center, which included embedded representatives from the Red Cross and Salvation Army, directed 47 truckloads of bottled water to the area, and CVS and other drug stores brought in extra supplies of medication.

Despite the rhetoric from officials, the evacuation of New Orleans and surrounding parishes was largely voluntary, and by the time Mayor Nagin and other local leaders ordered mandatory evacuations, most people had already made their plans to leave.

Gustav has already proved to be a spectacular political hot potato. Sandwiched as it is between the Democratic and Republican national conventions, both the Obama and McCain campaigns have been working overtime to score political points by loudly announcing how they weren’t going to use Gustav to score political points.

This serves as a useful reminder of the fact that as long as government takes the top role in responding to and rebuilding after disasters, disasters will be politicized. When things as seemingly anodyne as bridge building are highly political, the idea of something as hot-button as natural disasters remaining apolitical is churlish.

The most important thing that public officials must bear in mind at this point is that the recovery process began yesterday. Much of the delay we’ve seen in rebuilding after Katrina has been caused by shifting rules of the game in rebuilding, as governments on all levels proved unable to make clear, credible commitments about what would be done and when.

Both the Obama and the McCain campaigns will be tempted to announce their plans for rebuilding programs. If the candidates are serious about helping the Gulf Coast, they’ll stay silent about particular plans, save the requisite cheerleading, and let the non-profit groups and entrepreneurs who have been doing the heavy lifting in the three years following Katrina get in with their jobs. For the last three years, officials on all levels of government have been raising expectations, only to renege on promises that were unlikely — or even impossible — to be fulfilled.

As the recovery effort gets underway, it’s critical that officials do not try to dictate the patterns of recovery. For the last three years, the most effective solutions to rebuilding the communities devastated by Katrina have relied on local knowledge that entrepreneurs, non-profit groups, community organizations, and groups of everyday citizens possess — and that nobody in Washington does.

To be effective, post-disaster recovery must be led by the people who have a stake — financial, social, and personal — in the success of the rebuilding. After the immediate needs are met, FEMA and other government groups need to pull back and avoid the temptation to try to micro-manage the recovery. A key lesson of Katrina is that grassroots, bottom-up efforts at rebuilding work, while top-down plans fail.

Government plays a role in this by supporting the people who are getting the work done, not by dictating to them. This means making and following through on commitments to things like reopening schools, road cleaning and maintenance, respecting property rights, and allowing freedom of contract. In this environment, grassroots solutions can thrive, and the affected areas will rebound more quickly and sustainably.

Perhaps the greatest fear at this point is that, with Gustav having been a much less destructive storm that was promised, people on the Gulf Coast will be reluctant to leave the next time a hurricane approaches. This was certainly the case after Katrina: many people chose not to leave because they had survived other storms without so much as a scratch. The phrase “mandatory evacuation” will pack less punch next time. As with terrorism, our vigilance and sense of trepidation, so keen after an event, diminishes over time.

And worst of all, Gustav’s relative weakness may lead people to believe in the future that they can indeed rely on the government to tell them when to stay, when to go, and what to do during a disaster. Government resources have been stretched to the limit responding to Gustav. If the hurricane were as large as had been initially predicted — and had people chosen not to evacuate — we might well be witnessing another Katrina unfolding.

There are a number of policy reforms that still need to be made. Policy makers should consider serious repairs to federal policies on everything from levee construction to the National Flood Insurance Program. And many of the touted post-Katrina reforms did not get tested this time, or are yet to be implemented.

In the coming days, we will see whether policy makers and presidential candidates have learned the real lessons of Katrina about the role that the private sector and grassroots action play in post-disaster recovery. These days will have massive implications for the months and years ahead.

Mr. Rothschild is the director of the Gulf Coast Recovery Project at the Mercatus Center at George Mason University in Arlington, Va.