Experts agree that, at the very least, the plaintiffs are attempting to break a new legal path. Like many environmental statutes, the ESA includes a provision that lets private individuals file suit against anyone they believe is violating the law, as long as they can demonstrate some sort of personal stake or injury. These kinds of citizen suits aren't rare, but they are usually aimed at protecting fauna that is still in its natural habitat, says David Favre, a professor of animal law at Michigan State University who has been closely following the Ringling Bros. suit.
"The ESA until now has more or less dealt with nameless animals in the wild," Favre says. "This is the first time its dealing with wildlife in a captive situation."