This morning, the Supreme Court denied review in Desert Water Authority & Coachella Valley Water District v. Agua Caliente Band of Cahuilla Indians. The water district petitioners had asked the High Court to review the Ninth Circuit’s precedent-setting decision holding that the doctrine of federal reserved water rights is not limited to surface water, and thus that such rights can be asserted in groundwater. Our brief supporting the petition argued that Supreme Court review was merited given the lower court’s failure to address how extension of the so-called Winters doctrine to groundwater might result in the unconstitutional taking of groundwater rights. The Supreme Court’s refusal to hear the case may not, however, reflect a lack of interest in the underlying issue. It instead may be a function of this case’s posture—the Ninth Circuit held only that a federal reserved water right could exist in groundwater—whether and to what extent the Agua Caliente Band is entitled to the use of any particular quantum of groundwater, or damages for others’ unauthorized use of that quantum, remains to be decided on remand in the district court.