Indirect Land Use Change (ILUC) refers to deforestation and agricultural expansion due to increased crop prices. It is a controversial spillover effect of biofuels that is estimated by "shocking" agricultural market models with high biofuel scenarios. The validity of this modeling is highly contested in biofuel regulation. As a case study of ILUC discourse, this chapter analyzes how ILUC science was interpreted and strategically framed during rulemaking for the California Low Carbon Fuel Standard (LCFS) in 2007-2009. The analysis covers three stages of the initial rulemaking process: academic advisory reports, agency rulemaking documents, and public comments. It finds that at every stage, stakeholders blended values-based and science-based arguments. Even when stakeholders framed their stances as firmly based on science, their interpretation of "right" action in the face of uncertainty also depended on normative values. The takeaway for policy-makers is that ILUC is not an issue where policy answers can be straightforwardly derived from science.