Joseph Blocher wonders what happened to the days of the Lousiana Purchase and Seward's Folly:

Somewhere along the way, the market for sovereign territory seems to have dried up, at least as far as I can tell. To be sure, there is still an active market for proprietary interests in public land; the federal government, after all, owns approximately 30% of the nation’s land. But borders–sovereign territory, rather than property–do not seem to be for sale, especially domestically. Why? 

One possible explanation is that there’s simply no demand, but that doesn’t seem quite right. It’s not hard to imagine situations in which some state-to-state Coasean bargaining might create mutual gains. California could shore up its budget by selling land to Oregon. Some of the dozens of major interstate metropolitan areas straddling state borders could be consolidated. Or when Martha’s Vineyard voted to secede from Massachusetts in the 1970s (yes, really), and Kansas expressed interest in acquiring it (yep), a deal might’ve been struck that would’ve left the Bay State richer and Kansas with … well, a bay.