Katrina and its aftermath left us with many lessons but none more powerful than this: There’s no such thing as a blank slate.

The idea that post-Katrina New Orleans was exactly that was understandably tantalizing in some circles, and not just among those with ugly motives. Yet, the notion also turned out to be spectacularly tone-deaf.

Sure, there were plenty of disaster capitalists and at least a handful of white leaders who talked of changing the city “demographically, geographically and politically,” as businessman Jimmy Reiss said in an infamous Wall Street Journal account. But there also were lots of well-intentioned idealists in blank slate camp — people from Louisiana who saw the disaster as a chance to break old patterns and build a better, smarter, safer place, and experts from around the world who saw an opportunity to test their big ideas in the real world. The real world, it turned out, had its own ideas.

The most famous reality check came in early 2006, when Mayor Ray Nagin’s Bring New Orleans Back Commission introduced a rebuilding blueprint, informed by planning experts from the Urban Land Institute, that would have focused rebuilding in some neighborhoods and envisioned allowing others to revert to green space. The timing was terrible. Meant to provide direction and show Washington that there was a plan, it instead sent a message that decisions about their own homes were being taken out of homeowners’ hands and made behind their backs. The response was ferocious, and the very thought that government would take a strong hand pretty much died on the spot. Instead, the event launched what became a house-by-house and neighborhood-by-neighborhood effort determined by what Nagin liked to call the “free market.”

I spoke to people involved in the ULI effort recently, and they cautiously contended that they’d gotten a lot right. It does make sense to build in areas that are less environmentally vulnerable, to be realistic about available resources and cluster development for greater efficiency, to offer people reliable information before they have to make the hardest decisions of their lives. They also noted that they envisioned offering resources to help make people who moved whole and that what’s emerged in some areas is the scattered redevelopment they’d hoped to avert. Perhaps if they’d waited longer, given people more time to mourn, they said, people might have been more receptive.

In retrospect, I doubt it, and not just because residents didn’t have the luxury of waiting for emotions to subside to figure out where they could live.

The idea of central planning — pushed, ironically, by some leading Republicans and fought by Democrats who embraced the individual, customer-driven approach — demanded an actual blank slate. Yet, even the ruined landscape was loaded — littered with property lines and shaped by difficult history.

In a vacuum, it makes sense to argue that residents should migrate toward the higher ground that was settled before the city figured out how to pump water out of low-lying swampland. But factor in the reality that those areas included vibrant, mostly African-American communities and were home to families who settled there because the high ground was taken by the time they could buy homes — and you’ve got a different story.

In a vacuum, why not expect residents to trust that the big thinkers will make sure everything is fair , a principle that’s mentioned repeatedly in the ULI report? Well, one reason is that it doesn’t jibe with people’s experiences.

And 10 years into the recovery, there’s lots of evidence that those who didn’t trust the system to be fair were right. The Road Home rebuilding program that helped many thousands recover wasn’t intended to favor some over others, but even seemingly value-neutral rules had disparate impact. Most glaring was the initial decision to reimburse homeowners based on their prestorm value, which led to wide discrepancies on payments based on where homeowners lived, even though the cost of rebuilding was the same everywhere. Add in the program’s focus on homeowners as opposed to renters, and there’s another level of inequality. Should people have put more faith in the system? It’s hard to argue so.

Still, I have to confess to still having some sympathy with the master planners. For all the people I interviewed back in the early days who chafed at the thought of being told what they could or couldn’t do with their own property, I met just as many who desperately wanted to know if their neighborhoods would have stores, police protection, hospitals and people before deciding. The free-market recovery that emerged from the ashes of the BNOB process was kind to some but cruel to others.

I’m not sure things could have gone differently, and the pioneers who fought their way back deserve all the credit in the world. Their efforts, just like everything that set the stage before Katrina, are now part of the city’s history, too. We can only hope that the well-meaning, smart people who study them learn the right lessons for next time.

Stephanie Grace can be contacted at sgrace@theadvocate.com.