How can the Constitution protect landowners from government exploitation without disabling the machinery that protects landowners from each other? The Supreme Court left this central question unanswered — and indeed unasked — in Koontz v. St. Johns River Water Management District. The Court’s exactions jurisprudence, set forth in Nollan v. California Coastal Commission, Dolan v. City of Tigard, and now Koontz, requires the government to satisfy demanding criteria for certain bargains — or proposed bargains — implicating the use of land. Yet because virtually every restriction, fee, or tax associated with the ownership or use of land can be cast as a bargain, the Court must find some way to hive off the domain of exactions from garden variet...