The theoretical approach thus shows a new transatlantic bargain characterized by both realist and liberal elements, combining strategic and military cooperation with deeper economic interdependence. If successfully implemented, this will allow the EU and the US to face transnational and multidimensional threats emanating from the EU southern neighborhood, the Middle East and North Africa, as well as the more traditional kinds from the East. An institutionalist approach will be applied to NATO’s evolving position towards cyber security and defense. This new development is one of the most compelling outcomes of NATO’s Wales summit in September 2014. Last but not least, the bottom-up approach will be used to investigate and explain how institutional transformations and policy decisions related to the transatlantic security and defense partnership could be influenced by practitioners, academics and experts in the field.