But in built form the project, which scattered benches, daybeds, a foosball table, a bike-repair station, and other items across PS1’s spacious concrete courtyard, was both skimpy and desultory. On the day I visited, the canopy flapping overhead, described in the press materials as “elegant and taut,” was neither. The space below was almost entirely empty, making even people-watching, usually the best part of any YAP design, impossible. Frankly, as an example of built architecture—as a series of spaces to navigate and objects to sit on or touch—it was all a bit sad.

Figuring out where the project went wrong—or if it went wrong at all—strikes me as the distillation of a key dilemma now facing humanitarian design. What happens when a building or an installation is more sophisticated in social than formal terms, or works well when seen up close but looks terrible in renderings and photographs? Such projects tend to falter in an architecture culture ill-equipped to make sense of them or show them to their best advantage.

Architects trying to work at the broader scale of the city—particularly in helping to shape post-disaster rebuilding plans—find an even more daunting series of obstacles. The most obvious and difficult issue to grapple with is the way that truly civic-minded urban planning—as a profession, and as a social good that government is willing to pay for—has withered almost completely in the United States.

It would be a mistake to see the rebuilding fiascos at Ground Zero and in New Orleans as identical, or to try to understand them solely in terms of humanitarian design. But taken together they offer a painfully clear portrait of a nation that has either rejected the need for or decided it can’t afford real planning—and therefore has made the job of socially committed architects drawn to the urban scale remarkably tough. In Lower Manhattan, the bureaucrats overseeing the rebuilding process lurched from one planning extreme to the other: First they trotted out six reserved and unimaginative design studies by the New York firm Beyer Blinder Belle, only to reverse course and hastily throw together an international competition to pick a lead master planner for the site. That competition’s list of finalists was made up almost entirely of architects—and world-famous ones at that—rather than planners.

At no point did the site’s overseers manage to use the planning process to clarify the key issues and questions at the site, which would seem to be the point of the whole exercise. To begin with, was it wise to pack 10 million square feet of office space into a part of Manhattan where there was little demand for it, essentially repeating the mistakes the builders of the original World Trade Center made 40 years ago? Did it make sense to allow the site’s highly leveraged leaseholder, developer Larry Silverstein, to treat the rebuilding effort as just another deal in Manhattan, finding angles wherever he could, even as New Yorkers and the nation at large saw the site as anything but a typical patch of real estate?

As important as these questions were, they were repeatedly pushed aside during the rebuilding process, first by the dutiful blandness of the Beyer Blinder Belle approach and then by the powerful but manipulative metaphors of the master plan by Daniel Libeskind, AIA. Is it any wonder that what’s actually being built has so little to do with either of those blueprints? Or that it fails to follow either planning or architectural logic?

In New Orleans, architects couldn’t even manage, as Libeskind did, a Pyrrhic victory. The problem from the start with post-Katrina rebuilding was the absence of any larger planning framework with the muscle of public policy and government will behind it. Scores of talented architects—some funded by Brad Pitt’s Make It Right Foundation, others working with foundation grants, and still others operating as free agents—poured into the city in the months following the hurricane. What they found was a city planning agency, and a regional planning apparatus, so shell-shocked by the disaster and gutted by budget cuts as to be nearly impotent.

When I traveled to Louisiana a few months after Katrina and heard that the most sophisticated planning efforts were being funded and overseen by private philanthropies, rather than in any coordinated public way, it was easy to predict where things were headed. A number of prototypes for green, flood-proof housing followed. In a few cases architects and planners tried to address similar issues at the scale of a park or a stretch of waterfront. But all these efforts ended up floating in a larger sea of indifference—in an unplanned urban matrix—severely limiting their impact and meaning.

When it comes to disasters of Katrina’s magnitude, in literal as well as symbolic terms, architecture can do only so much. No shiny rendering can make up for a flimsy or non-existent planning strategy in areas undone by a hurricane, a terror attack, or decades of poverty. There is no such thing as a Bilbao Effect for disaster relief. (And remember, in any event, that the Bilbao renaissance itself was driven by smart planning and infrastructural investment.) No single building, no matter how brilliant, can overcome a lack of coordination between architectural goals on the one hand and economic and political ones on the other.

Architects can certainly take it upon themselves to sharpen their skills in community organizing and lobbying. But to really galvanize humanitarian design will require changes outside its ranks. Architecture schools will need to do a far better job at teaching students to navigate political and fundraising mazes, and to think strategically about the connections between design and social policy. Planners will have to either reinvent their own profession or begin to cede some of their responsibilities to others, including architects. Journalists and bloggers will have to think of better ways to describe and judge projects that are more concerned with community development than pure aesthetics.

These issues are made all the more complex because humanitarian design is by definition wildly diverse. It will never be a singular movement organized around formal priorities. A young architect coordinating housing plans for tsunami victims certainly has something in common with one building schools for the poor in Texas or a green high-rise in Rio de Janeiro. But not nearly as much as Gordon Bunshaft had with Walter Gropius.

Modernism remade the world, for better and worse, with an architectural philosophy that was like a blade: very simple, very sharp, and ultimately very detached from the sites of its surgical mastery. Humanitarian designers are trying to remake it by rolling up their sleeves and digging directly into the literal and symbolic dirt—or, more often, the muck of a flooded or disaster-strewn site. The results are bound to be messier and harder to measure. At the same time, as we move inexorably into an age of disaster, the stakes are higher this time around—for architects, maybe, but without a doubt for the parts of the planet they’ll be rushing to heal and repair.