In this episode of NATO's Road to Madrid, Rachel sits down separately with two guests to discuss the alliance's original and most core function: deterring and defending against threats to NATO members. The first segment is an interview with Jessica Cox, the Director of the Nuclear Policy Directorate at NATO. Rachel and Jessica break down the alliance's nuclear posture and how it is responding to changes in Russian nuclear policy and new additions to its dual-capable missile arsenal. In the second segment, Rachel interviews Mike Mazarr, a Senior Political Scientist at the RAND Corporation. Mike helps to explain how non-conventional and hybrid threats have made the development of deterrence concepts across multiple domains extremely difficult, for both the United States and NATO alike.