This paper examines how international education (IE), as an important tool of public diplomacy (PD) and soft power (SP), faces unique challenges as issues of national security (NS) become more prominent in this era of new geopolitics. It presents a model to understand the relationship between PD, SP and NS and then applies this model to a comparative study. The contrasting histories, approaches and perspectives of IE as it operates as a component of foreign policy and at the nexus of PD, SP and NS in both the U.S. and Canada are analysed. The paper concludes with three challenges faced by IE in the contemporary context: first, the diminishing role of the university as a distinct and valued non-state actor; second, the weakening of foreign policy as an outward looking, distinctly international investment; and third, the problem with choosing isolation over engagement as a strategy.