This chapter aims to locate the critical juncture when securitization is – from a moral point of view – not merely permitted (and thus optional) but obligatory (mandatory). This chapter argues that securitization is morally obligatory (pro tanto) when ‘must cause’ is satisfied. This is the case when would-be securitizing actors have tried relevant less harmful alternatives and when these have failed to satisfy just cause. This view is in line with supererogationism a philosophical position that sees value in keeping morality – where possible – free from prescriptive behaviour whereby every good and right generates a moral obligation. It is argued that the value of autonomy that allows relevant actors (limited) freedom to choose on how to respond to a just cause for securitization diminishes as certainty that securitization is the best response increases. Certainty increases subject to evidence that less harmful options than securitization do not work. This chapter goes on to discuss must cause in detail on six illustrative hypothetical examples of different threat types, including drought disaster, cyberattack, and climate disaster.

This chapter considers the impact of the discovery of mandatory securitization on global security institutions. While ties of community and friendship, specifically at the sub-systemic level, ensure that the burden of mandatory securitization on the international community is relatively small, the international community – in the form of the UNSC – is obligated to act when (1) states or sub-systemic actors fail (note, in other-securitization they may fail for legitimate reasons), or (2) where there is no other designated protector. This chapter suggests that the UN charter amounts to a social contractual situation between the people of the world and the UNSC, rendering its duty to securitize – when conditions are met and there is no other protector – overriding. It goes on to examine the nature of these duties as they already exist by examining RtoP provisions. It shows that even if RtoP was in perfect working order and always acted on, it does not cover the moral duties of the UNSC regarding securitization; notably, it does not cover intent-lacking threats. Much like in Chapter 4 where mandatory securitization is used to update NATO’s Article 5, this chapter shows how mandatory securitization can refocus and thus help RtoP.