[JURIST] The US Court of Appeals for the Seventh Circuit [official website] ruled [text, PDF] Monday against a coalition of five Great Lakes States seeking to compel the Army Corps of Engineers [official website] and the Metropolitan Water Reclamation District of Greater Chicago (District) to take action to prevent Asian carp [NWF backgrounder] from entering Lake Michigan through the Chicago Area Waterway System (CAWS). The suit brought by Michigan, Wisconsin, Minnesota, Ohio and Pennsylvania sought to compel the Army Corps to take a “number of aggressive interim measures to maximize the chance of preventing the spread of the carp.” The court found that the “States have not alleged facts showing that the Corps and the District are operating the CAWS in a manner that is likely to allow Asian carp to reach Lake Michigan.” The court however left open the possibility for future suits by the five State coalition stating, “as we did before, we leave open the possibility of relief should there come a time when reliable fact show the carp pose a more immediate threat to the Lakes…” A press release [text] from Wisconsin Attorney General JB Van Hollen expressed disappointment in the court’s decision, but also praised the court’s rejection of the Army Corps’ argument that it has no responsibility to run the CAWS in such a way as to prevent invasive species from entering the Great Lakes.

The Seventh Circuit’s ruling is only the most recent chapter in a legal battle that has been going on for years. In 2012 the US District Court for the Northern District of Illinois [official website] dismissed [JURIST report] the nuisance suit in which the Seventh Circuit Monday. The US Supreme Court denied a petition for writ of certiorari [JURIST report] in the five states’ Asian carp suit for the fourth time in February 2012. In August 2011 the Seventh Circuit ruled against [JURIST report] the states’ efforts to stop the Asian carp. The Supreme Court had denied certiorari [AP report] on the issue three times as of April 2010. In December 2009 the state of Michigan filed a lawsuit [JURIST report] in the Supreme Court against the state of Illinois seeking to close the two waterways, as the court has original jurisdiction in disputes between the states. All three times, the court denied certiorari without comment on the dispute. Michigan reopened the longstanding controversy [backgrounder, PDF] over the diversion canal, created in the 1890s to keep Chicago’s sewage from flowing into Lake Michigan.