This study analyses the Actorness Cohesion (AC) of the EU’s foreign policy in the United Nations General Assembly First Committee by comparing the EU Delegation foreign policy-maker’s role conceptions to those made by the EU Member State (EU MS) Delegations on the same topic clusters. The concept of AC is developed from actorness and role theory as an ideational, constructivist measure of vertical policy coherence. AC represents the absence of ‘vertical conflicts’ between the EU and EU MS Delegation’s expressed role conceptions along four dimensions; Identity Cohesion, Goal Cohesion and Function Cohesion and Worldview Cohesion. This is studied by interpreting the role stability in the role-set; whether the contents are consistent, the EU role conception is central or whether the EU MS Delegations complement and/or are compatible to the EU role conception. Statements on topic clusters: ‘Disarmament Machinery’, ‘Conventional Weapons’ and ‘Outer Space (disarmament aspects)’ are analysed in order to determine the AC. The study concludes that whilst there is little evidence of the EU Delegation’s role conception being central to the EU MS Delegations, there is considerable consistency of contents. There are also indications of an emerging AC due to the EU MS Delegation’s role conceptions being complementary to that of the EU Delegation. The study calls for more research that will complement this plausibility-probe study and the concept of AC.