Sometime this fall, a group of mayors from metropolitan Chicago will do something unusual by local custom. They will talk to one another.
Presiding over this "summit" will be Chicago Mayor Richard M. Daley, who told suburban leaders last month that it was time for communities across Chicagoland to stop quarreling and start addressing regional challenges together.
A decade ago, Mr. Daley's invitation would have been viewed with extreme suspicion. To suburbanites, Chicago was the kind of neighbor who only showed up when he needed to borrow something from your toolshed.
But these days, the roles are changing. Across the nation, cities like Chicago are marching back, while their closest suburbs are showing signs of decay. Civic leaders are warming to the notion that problems like crime, congestion, pollution, shrinking budgets, and changing labor markets might benefit from a regional focus.
For America's metropolitan areas, it's a crucial moment. Unless cities and suburbs learn to manage their growth in a cooperative fashion, experts say, the forces of suburban sprawl will continue to spread their resources to the breaking point.
"Over the last 25 years, it has become clear that cities of all sizes can't function as isolated economic entities," says Carl Abbott, an urbanologist at Portland State University in Oregon.
Today's national economy, Mr. Abbot says, is driven by competition between a new breed of "city-states" that encircle urban centers. Rather than compete against one another for outside investment, he argues, neighboring communities ought to search for ways to pool their resources.
"It's not Detroit vs. Livonia or Auburn Hills or Grosse Pointe," says Detroit Mayor Dennis Archer, who has worked to improve ties between his city and the 239 municipalities that surround it. "It's Detroit vs. Cleveland, so it's in our best interests to come together collectively."