New England states could pass as many regulations as they wanted, but they were meaningless unless Midwestern states acted. Crabbers on the Chesapeake Bay depend on the behavior of farmers from five states—New York, Pennsylvania, Virginia, Maryland, New Jersey, Delaware—and Washington, DC. The Mississippi River’s watershed touches 31 U.S. states and 2 Canadian provinces. It’s hard to think of bi-lateral agreements that could control that. In fact, we know from experience that it was pretty much impossible.