State wildlife agencies commonly claim they are entitled to manage wildlife under the public trust doctrine (PTD). This assertion is frequently made in judicial proceedings, with state requests that their managerial authority be given due force throughout state, private, federal, and even tribal lands. One might conclude that a rich body of PTD practices and policies exists for wildlife; in reality, the PTD in state wildlife management proves to be ephemeral. This Article empirically investigates application of the PTD to wildlife by 13 state fish and wildlife agencies in the American West over nearly two decades. It exposes a significant gap between the legal assertions western states make about the PTD and the actual decisions of state agencies. To fulfill the legal mandate of the PTD, and avoid the specter of arbitrary and capricious decisionmaking, state wildlife agencies must do more. The Article suggests how states can begin to close this implementation gap.