New ways of understanding securitySecurity and securitySecurity threats have emerged over recent decades, in large measure because global climate change is promoting common, yet unprecedented, challenges. These new threats, and responses to them, have played out in ways unique to the North American Arctic. Taken together, Canadian and American approaches to international, economic, and defence issues draw from perspectives distinctive to North AmericaNorth America, while the uncertainty produced by new threat and securitySecurity scenarios are increasingly reinforced by a changing international order. This includes the relationships between North American states, as well as between North America and the world. This chapter explores the evolution of security narratives within defence and international agencies over the recent past, and the way in which security threats are understood and enacted by policymakers as well as by security actors and practitioners. The chapter discusses the move to “widen” the concept of security and distinguish between “hard/traditional” and “soft/non-traditional” security threats within Arctic security narratives, which occurred often in tandem with events encouraging renewed militarization of the Arctic. The chapter follows the way in which two North American states—Canada and the USA—have positioned both traditional and non-traditional security concerns within policy and practice related to the Arctic.