The transfer of some decision-making authority from the domestic to the supranational arena as a result of the establishment of the World Trade Organization (WTO) in 1995 potentially changed domestic policy dynamics. The WTO agreements reflect the trade policy concerns addressed in the Uruguay Round in the late 1980s and early 1990s. This article applies and adapts historical institutionalism to explain how international organizations may constrain and facilitate certain domestic policy options. It demonstrates that, while the WTO legal framework has become more receptive of environmental sustainability concerns, the social sustainability concerns that were increasingly entering the debate over biofuel policies were not easily accommodated, and this was seen as a constraint on the content of the European Union's (EU) policy adopted in 2009. Only the environmental dimension of a broader concept of sustainability was included in the policy design.