Objective We ask whether framing U.N. actions in terms of institutional origins or multilateral support has differential effects on attitudes toward environmental sustainability policy. Methods A survey experiment exposed individuals to different descriptions of U.N. Agenda 21, a 1992 sustainable development policy document. Results Individuals who learned about Agenda 21 in terms of the international consensus behind the document at its inception were significantly more likely to support it and find it important. Conservative individuals who learned Agenda 21 was a U.N. document were significantly less likely to believe it was important and to want the federal government to incentivize implementation. Conclusions Framing U.N. action in terms of international consensus may be a gateway toward building support among Americans in general. Framing U.N. action in terms of the institution behind the action has little effect on opinion, except in some instances when it turns conservatives against said action.