LAST SUMMER, in the case of Kelo v. New London, a bitterly divided U.S. Supreme Court upheld (and slightly expanded) the constitutionality of local governments’ seizing private property for economic development via the “takings power” of eminent domain. But in his majority opinion, Justice John Paul Stevens took care to insert this sentence in the closing paragraphs: “We emphasize that nothing in our opinion precludes any State from placing further restrictions on its exercise of the takings power.”