From Geocurrents, Asya Pereltsvaig on the geography of sin in the US. The Centroid: From the department of curiosities — a federal statistic that tracks the balance point of the U.S. population. From Journalist’s Resource, a research roundup on economic and social change in U.S. cities and urban areas. Aaron David Miller on how geography explains the United States: Our country remains uniquely secure from foreign threats — and that shapes how Americans see the world. America's seismic demographic shift is upending life in our suburbs, cities and our popular culture — so why are we still clinging to the same stories to make sense of these changes? Vulnerability in an open city: Urban life means risk — that’s why we live here. Go ahead, secede already: Lee Siegel on why the South should get the hell out of the union. Joel Kotkin on the triumph of suburbia. Anna Clark on the tyranny of the ZIP Code: They don't just locate us — they define us.