The Akimel O'odham, or "River People" (Pima), have lived in the middle Gila River Valley for centuries, irrigating and cultivating the same land as their Huhugam ancestors did for millennia. Continuing their irrigated agricultural economy bequeathed to them by their Huhugam ancestors, the Pima leveraged a favorable geopolitical setting into a viable and sustainable agricultural economy that resulted in economic prosperity. Accordingly, they sought inclusion in the emerging American economy of the Southwest and by the late 1840s were an economic force in the middle Gila River Valley. Emigrant settlement above the Pima villages eventually deprived the Indians of the water needed to sustain their economy. This undermined their agricultural economy and by the 1890s, they faced the pangs of hunger and poverty and became dependent on the US government for subsistence. This article argues that the Pima had a well-established and successful agricultural economy that was destroyed by the effects of federal land and federal Indian policies. The rhetoric of agrarian assimilation underlying federal Indian policy failed to match the reality of the Pima, and federal land policies further eroded the application of such policies. Rather than enabling the Pima to participate in the national market economy, the effects of economic liberalism forced the Indians into a dependent state that undermined their economy and economic well-being. Economic liberalism as a socioeconomic and political philosophy used by the United States to foster settlement of the West enabled settlers, speculators, and politicians to manipulate its application to their advantage and dispossess the Indians of their resources. (Contains 1 figure, 6 tables, and 11 notes.)