ABSTRACT. The 1964 Columbia River Treaty between the United States and Canada is currently under review. Under the treaty, the river is jointly operated by the two countries for hydropower and is the largest producer of hydropower in the western hemisphere. In considering the next phase of international river governance, the degree of uncertainty surrounding the drivers of change complicates efforts to predict and manage under traditional approaches that rely on historical ecosystem responses. At the same time, changes in social values have focused attention on ecosystem health, the decline of which has led to the listing of seven salmon and four steelhead populations under the U.S. Endangered Species Act. Although adaptive management is considered one approach to resource management in the face of uncertainty, an early attempt at its implementation in the U.S. portion of the basin failed. We explore these issues in the context of resilience, taking the position that while adaptive management may foster ecological resilience, it is only one factor in the institutional changes needed to foster social-ecological resilience captured in the concept of adaptive governance.