Political debate about the endangered Steller sea lion turns on uncertainty about the cause of decline and lack of recovery of this marine mammal of the North Pacific Ocean. To shift the political terrain, different groups tried to shift the scale at which problems are framed. US regulators focused on localised interactions, environmental organisations highlighted the entire fishery management regime and the fishing industry focused on natural climate change within the North Pacific region. Because debate is about supposedly objective, scientific realities, these practices of scale framing take on particular significance in this case. Scientific understandings of individual problems are not outside the frame of scale practices, but instead there is a politics of scale around science. This case shows that using scale as a framing device is a powerful political strategy for dealing with uncertainty, because focusing on a particular scale presupposes certain kinds of solutions while foreclosing others.