The paper aims to analyse a unique era in Turkish-American relationsthrough discussion on the arms sales embargo imposed by the United States onTurkey as a consequence of Turkish military intervention in Cyprus in 1974. It triesto highlight the strife between the legislative and executive branches of US politics,where both have altered on the embargo case. The role of ethnic lobbies is another element that is questioned. An institutional explanation is used as a theoreticalframework. In conclusion, the paper says that the embargo had negatively affectedUS-Turkish relations and paved the way for the weakening of the south-easternflank of NATO