The European Union (EU) military Operation Headquarters (OHQ) construct has been described as a slow starter due to familiarization issues and an arena for parallel chains of command. Similarly, a recent study of a live OHQ showed national perspectives to be common, particularly with staff members from nations prominent in the operation. However, the nature of these flaws remains unclear while scholars debate if the EU OHQ can and should move towards civil-military integration. This paper investigates individual's national perspectives in an experimental setting with 180 civilian and military professionals related to crisis management. Manipulations include parent-nation prominence, familiarity with response units, and participants’ ties to the parent-nation. The results show that national units are significantly favoured when more familiar to the participant compared with foreign units and when representing a minority in the multinational context. This partly mirrors previous findings. Importantly, no significant difference appears between military and civilian participants. It is concluded that the OHQ construct may be flawed by design by requiring a familiarization process, but that OHQ cohesion in terms of receptiveness to national influences would not necessarily change with civil-military integration.