“Navigability”—the degree to which a particular water body can be used by various boats and other watercraft—has a long, important history in federal constitutional and statutory law. U.S. Supreme Court cases involving navigability helped to shape the scope of federal authority under the Commerce Clause and the Necessary and Proper Clause of the U.S. Constitution. The legal concept of navigability has also been critical in defining private versus public property rights in water bodies, allocating property between the federal and state governments, and delineating the scope of Article III federal court admiralty jurisdiction. Navigability also played a key role in the evolution of various common law doctrines, and the connections between those doctrines and the Constitution remain unclear.
Given this pedigree, to borrow from the poet Coleridge, wherefore should we stop today to question the relevance of navigability to constitutional law? In several ways the role of navigability in constitutional law began to decline long ago. Dramatic changes in the U.S. economy and in our understanding and valuation of aquatic ecosystems and resources help explain why navigability may be even less important today than it has been in the past. The role and significance of navigability, however, varies greatly depending on the purpose of the differing legal doctrines for which it is used.
During its October 2011 term, for the first time in more than three decades, the U.S. Supreme Court decided a case about the meaning of the term “navigability” to establish “navigability for title,” i.e., whether a state holds title to the beds and banks of its waterways under the equal footing doctrine of the U.S. Constitution and for purposes of the public trust doctrine as defined by that state’s law. The Court granted certiorari on the single issue of whether the Montana Supreme Court applied the correct federal legal standard for determining whether the Missouri, Clark Fork, and Madison Rivers were navigable at the time of statehood. Petitioner PPL Montana (PPL) raised three narrow challenges to the Montana Supreme Court’s approach to determining navigability for title: first, whether the Montana court focused on the navigability of particular river segments rather than the river as a whole; second, whether the Montana court erred by considering evidence of current-day navigability as probative of navigability at statehood; and third, whether the Montana court employed too liberal a standard for navigability. The U.S. Supreme Court ruled unanimously in PPL’s favor on the first two issues, holding that the seventeen-mile Great Falls reach of the Missouri River was not navigable for title and remanding with respect to the remaining disputed segments. Given the Court’s unanimous decision on evidentiary grounds, why is this case important?
At a basic level, PPL Montana will dictate the litigation burden states will bear in proving navigability for title, and in some cases, their ability to do so at all. In PPL Montana, the State offered as evidence a fascinating set of historical records, including the journals of the Lewis and Clark expedition, which navigated many of the waters in question in dugout canoes in the early nineteenth century. PPL argued that historical records and expert affidavits regarding authenticity were inadmissible hearsay because no one alive today can testify to the validity of historical accounts based on personal knowledge. If neither historical records nor current evidence of navigability may be used, however, it is not clear what evidence would be both probative and admissible on the issue of navigability at statehood, making it difficult if not impossible for a state to prove its case. Except perhaps in Alaska and Hawaii, no one alive today can testify to navigability at statehood based on personal knowledge or observation.