Agricultural systems are situated within social and political environments that have tremendous influence on how they operate. If agricultural systems are to be sustainable, it is critical to understand how they are influenced by social and political factors. An expert panel approach was used to identify and rank the importance of social and political factors on agricultural systems in the US and to provide some insights into their impacts, interactions and mechanisms of influence. The panel identified a wide range of social and political factors that affect agricultural systems. The factors were divided into three categories: internal social factors, external social factors and political factors. Factors from each of the three categories were highly ranked, indicating that no single category dominated the others. Although there were contrasting views about the importance of some factors, there was strong consensus about many of them. Globalization and low margins that require increased scale and efficiency were identified as the two most important factors affecting agricultural systems. Several newly emerging factors were identified as well as factors needing further research. A comprehensive understanding of these factors is imperative to help guide scientific research so that beneficial discoveries are accepted and used, and to ensure that policy decisions enhance the future sustainability of agricultural production.