THE country has fallen on hard times, but those of us who love cities know we have been living in the dark ages for a while now. We know that turning things around will take more than just pouring money into shovel-ready projects, regardless of how they might boost the economy. Windmills won’t do it either. We long for a bold urban vision.

With their crowded neighborhoods and web of public services, cities are not only invaluable cultural incubators; they are also vastly more efficient than suburbs. But for years they have been neglected, and in many cases forcibly harmed, by policies that favored sprawl over density and conformity over difference.

Such policies have caused many of our urban centers to devolve into generic theme parks and others, like Detroit, to decay into ghost towns. They have also sparked the rise of ecologically unsustainable gated communities and reinforced economic disparities by building walls between racial, ethnic and class groups.

Correcting this imbalance will require a radical adjustment in how we think of cities and government’s role in them. At times it will mean destruction rather than repair. And it demands listening to people who have spent the last decade imagining and in many cases planning for more sustainable, livable and socially just cities.