This paper focuses on the role of interest groups in US sanctions policy toward Iran from 2007 to 2016. The aim of this work is to explain what changed in regard to the role of interest groups in the most significant shift in US-Iranian relations under President Barack Obama before and after the vote on the Joint Comprehensive Plan of Action, which was intended to halt Iran’s non-peaceful nuclear program in return for an easing of sanctions by the US Congress. This study contributes to our knowledge about how structural variables, issue salience, and actor strategies work together to produce outcomes. In addition, it provides a better understanding of interest group influence by identifying conditions under which interest groups can be successful in changing the policy status quo. This research proposes that the once firm stands of the Democrat legislators on supporting Iran sanctions changed due to support of President Obama’s strategy of engagement by Pro-Diplomacy groups and the international community, which he used as legislative subsidy. In addition, favorable policy windows opened up opportunities that pushed for diplomacy instead of confrontation.
