In 2010, the states of Michigan, Minnesota, Ohio, Pennsylvania and Wisconsin sued the United States Army Corp of Engineers and the Metropolitan Water Reclamation District of Greater Chicago, seeking injunctive relief aimed at preventing Asian carp from entering into Lake Michigan through the man-made Chicago Area Waterway System ("CAWS"), which connects Lake Michigan to the Mississippi River. The plaintiffs claimed that the defendants were managing the CAWS in a manner that will allow the invasive Asian carp to move into Lake Michigan and thereafter the other Great Lakes, causing an ecological disaster that amounts to a public nuisance under federal common law. The district court for the Northern District of Illinois denied plaintiffs' request for a preliminary injunction seeking, among other actions, the closure of the City of Chicago locks connecting the CAWS to Lake Michigan.
The denial of the preliminary injunction was appealed to the United States Court of Appeals for the Seventh Circuit. In a detailed 57-page opinion, Judge Wood, writing for a unanimous 3-judge panel, affirmed the district court's denial of the preliminary injunction. The court explained that to justify a preliminary injunction, the plaintiffs must show (1) that they are likely to succeed on the merits, (2) that they are likely to suffer irreparable harm without an injunction, and (3) that the harm the plaintiffs would suffer is greater than the harm that preliminary relief would inflict on the defendants. The appellate court held that the plaintiffs were sufficiently likely to succeed on the merits and that they were likely to suffer irreparable harm without the injunction, thus they met the first two elements necessary for a preliminary injunction.
The court touched on several issues in coming to its decision on the first two elements. First the court held that federal common law properly applies to the nuisance created by Asian carp. The court also addressed the question of whether a state can bring a common law public nuisance claim against the federal government, but declined to directly decide the issue because the case was resolved on other factors. In addition, the court held that sovereign immunity did not bar the case because sovereign immunity was waived for these types of claims under the Administrative Procedure Act. Finally, in a discussion that heavily cited the U.S. Supreme Court's recent decision in American Electric Power v. Connecticut, 131 S. Ct. 2527 (2011), the court held that federal common law was not displaced by federal legislation related to invasive species. In order for federal legislation to displace federal common law, it must speak directly to the question at issue. The court held that, unlike the Clean Air Act or Clean Water Act, federal legislation on invasive species does not directly speak to the public nuisance the plaintiffs are complaining about in this case.
Having established the first two elements necessary for a preliminary injunction, the court's decision hinged on its analysis of the third element, often referred to as a balancing of interests. The court held that the injunctive relief sought by plaintiffs was not likely to significantly reduce the threat caused by the Asian carp. In contrast, the injunctive relief would impose significant financial burdens on the federal government and the State of Illinois. Finally, even though legal displacement was not found, the court held that the extensive actions already being taken by the federal government to address the hazards posed by Asian carp displaced as a matter of fact any role an injunction would play in this case. The court stated that "there is nothing that any preliminary injunction from the court could add that would protect the Great Lakes from invasive carp while this suit is being adjudicated any better than the elaborate measures we have just described." The court cautioned, however, that if the level of government action, or the immediacy of the threat were to change in the future, the district court would have the authority to revisit the question of whether a preliminary injunction was warranted.
A copy of the Seventh Circuit's August 24, 2011, opinion is available here.