This is definitely the way to go. The key is the "Blue" cities and counties in the "Red" states. That's where the money is, and where the population is, in a number of states that went for Bush in 2004--Georgia, Florida, Ohio, and Colorado, for example.
To quote from the article:
In cities all over America, distressed liberals are talking about fleeing to Canada or, better yet, seceding from the Union. We can't literally secede and, let's admit it, we don't really want to live in Canada. It's too cold up there and in our heart-of-hearts we hate hockey. We can secede emotionally, however, by turning our backs on the heartland. We can focus on our issues, our urban issues, and promote our shared urban values. We can create a new identity politics, one that transcends class, race, sexual orientation, and religion, one that unites people living in cities with each other and with other urbanites in other cities. The Republicans have the federal government--for now. But we've got Seattle, Portland, San Francisco, Chicago, Los Angeles, San Diego, New York City (Bloomberg is a Republican in name only), and every college town in the country. We're everywhere any sane person wants to be. Let them have the shitholes, the Oklahomas, Wyomings, and Alabamas. We'll take Manhattan.