This preliminary study traces how climate change came to be viewed as a security issue in the United States through a review of policy documents and reports prepared for and by the US security sector.The paper draws upon the ideas of constructivist schools of security studies to provide an analytical framework for understanding the meaning of the securitization process as it has occurred in the United States.It then reflects upon the adequacy of those frameworks to interpret the securitization of climate change.In the US,new knowledge of the phenomenon of climate change was first constructed in the research sector,in the fields of meteorology and atmospheric science.Environmental and Earth sciences then became a locus of research,and climate change first entered security discourse as a topic of environmental protection.As the implications of climate change and its potential impact on water resources,food production,diseases,infrastructure,and human migration came to the attention of the security sector,this knowledge stimulated an inteal discourse,where each new document functioned both as a new securitization statement and as a policy response to prior documents in a chain of discourse.Actors in this securitization process included not only "speakers" making a securitization claim (knowledge claim) and "audiences" that accept or reject a claim.Importantly,it also included actors who were instrumental in translating knowledge between research and security sectors.This brief consideration suggests that social science theories that center on practice are more robust than those that center on discourse for interpreting the securitization of climate change.Improved analytic frameworks need to better account for actors whose role is to transfer and translate knowledge from one sector to another.