The present document aims at shedding light on the dynamics constraining the effective establishment of doctrines vis-à-vis the WMD proliferation in both the EU and the US. By means of a three chapters structure, this contribution intends to gradually demonstrate that, ultimately, neither the EU nor the US have managed to set up such documents by perpetuating the credibility deficit of the whole non-proliferation regime. Peculiarly, the first chapter reviews the literature indispensable to frame the EU and the US positions in the global context; the second one, after comparing the main EU/US strategy documents, drafts the limiting factors to the establishment of such comprehensive doctrines. The last chapter focuses on the empirical cases, namely Iran and India, allowing readers to understand how “exceptional”, eventually, the non-proliferation regime seems to be. Finally, conclusions and recommendations are drafted in light of what should be a possible way out for the “non-proliferation conundrum”.