On 24 June 2016 an event occurred that irreversibly changed the strategic direction of the European continent and its political identity. Through referendum over 30 million British citizens exercised their democratic right to determine their Nation’s future. The outcome resulted in BREXIT (The British Exit from the European Union). Whilst, the effects of BREXIT span the social, economic, political, demographic and cultural continuum; this paper will focus on the impact on defense and the consequences for the development of a future U.S. National Security Strategy. There is little doubt that this paradigm shift in British political philosophy will alter the U.S.’s strategic stance in some way. A cursory analysis suggests that the effect may simply be limited to the U.S. use of the UK as an interlocutor within Europe. However, Britain’s exit could influence broader security issues. These may include the ongoing UK involvement in support of operations against ISIS; the potential for a ‘UK pivot’ towards South East Asia and the maintenance of a comprehensive and holistic European response towards Russian expansion.