Interstate equitable apportionment of water

Josh Patashnik has posted "Arizona v. California and the Equitable Apportionment of Interstate Waterways" to SSRN. The article uses historical research and analysis to explain how and why the US Supreme Court arrived at its decision on interstate apportionment of water in Arizona v. California (1963):

Fifty years ago, the Supreme Court resolved a decades-long dispute between Arizona and California over the waters of the Colorado River. At the heart of the case’s legacy is a paradox of great significance. There is widespread agreement that the Court reached the right result, giving Arizona the water it needed to develop a dynamic, modern economy. Yet there is equally widespread agreement that the Court’s reasoning was wholly unpersuasive, resting on an egregious misreading of a thirty-five-year-old federal statute. How can this be? Was there no legally principled way to rule for Arizona, where the equities in the case lay?

Paul Hermans,  Horseshoe Bend, Page, Arizona

The answer is that the Court’s predicament was one of its own creation. In a series of rulings over the preceding half-century, it had placed prior appropriation — the time-honored Western water law principle of first in time, first in right — at the center of its doctrine of interstate equitable apportionment of water. This error threatened to make equitable apportionment distinctly inequitable in the Colorado River case.

This Article traces the Court’s equitable-apportionment jurisprudence over the first half of the twentieth century. Through original archival research, the Article seeks to demonstrate that a majority of the Court felt constrained in Arizona v. California by the rule of interstate prior appropriation, leading it to resort instead to the dubious piece of statutory interpretation that has been so heavily criticized. Because equitable apportionment and prior appropriation are fundamentally at odds, the Court would be better served by abandoning its (understandable) reluctance to employ a truly equitable, fairness-oriented balancing approach in dividing interstate waterways.