A/HRC/44/38 justifications should include “evidence of the imminence of an external threat and the proportionality of measures to be taken in response. Excessively expansive and unchecked interpretations of Article 51 are a threat to the international rules-based order and an obstacle to the promotion of international peace and security.”125 68. Yet, States have provided little by way of evidence for the imminence of the threats against which they have invoked claims of pre-emptive self-defence and targeted killings. The poor quality of the Article 51 submissions is compounded by the fact that States are not informed of their submissions as a matter of routine. An extensive study of Article 51 submissions by the Harvard Law School Program on International Law and Armed Conflict has shown that “Member States are apparently not made aware of such statements on the use of force as a matter of routine practice”.126 This is cause for significant concern, for it also means that the silence with which States most often meet Article 51submissions may not be deliberate or even conscious.127 69. The Security Council itself has offered little response to Article 51 claims. Academic analysis shows that the Council’s “most common reaction by far” to self-defence submissions is no formal response at all. From 1945 to 2018, “the Security Council responded formally – at least in the sense of a provision in an act of the Council or in a presidential statement – to only about one-tenth of the identified self-defense communications”.128 In those instances, the Council more often couched its reaction in political, rather than legal, terms, expressing concern but failing to offer a legal evaluation or recommend accountability and corrective action. Despite the many occasions on which the integrity of the Charter, the sovereignty of a third State and the right to life have been violated, in only one instance did the Council question the legality of an extraterritorial targeted killing. 129 The absence of formal engagement may result from the significant increase in the use of veto by permanent members of the Council, particularly over sensitive issues such as the use of force and targeted killings. A. States and the sound of silence 70. Member States too fail to respond publicly to cases involving pre-emptive selfdefence, including when drones are used. For instance, even in the face of the vast numbers of strikes on the Syrian Arab Republic by coalition forces between 2014 and 2017, while “several States have reacted … some with ‘legal vocabulary’, others using rather evasive language …, most States have remained silent.”130 71. Does the silence of States and other international actors represent acquiescence, as some scholars have suggested?131 The short answer is no,132 but the reasons for saying so are 125 126 127 128 129 130 131 132 Liechtenstein (S/PV.8699, p. 37). Dustin A. Lewis, Naz K. Modirzadeh and Gabriella Blum, Quantum of Silence: Inaction and Jus ad Bellum (Harvard Law School Program on International Law and Armed Conflict, 2019). Several mechanisms have been devised over time to ensure that that State and Security Council submissions on Article 51 (among others) are put together and shared. The preparation of many of the reports, however, is delayed by several years, making them of limited policy value, although this is not to reject the other contributions of such mechanisms. Lewis, Modirzadeh and Blum, Quantum of Silence. Security Council resolution 573 (1985). Paulina Starski, “Silence within the process of normative change and evolution of the prohibition on the use of force: normative volatility and legislative responsibility”, Journal on the Use of Force and International Law, vol. 4, No. 1 (2017), p. 48. These views are presented and analysed in Lewis, Modirzadeh and Blum, Quantum of Silence, pp. 70–79. As stated on 13 January 2020 by the Permanent Representative of Austria to the United Nations (www.bmeia.gv.at/oev-new-york/news/statements-and-speeches/alle-statements/2020/01/sc-opendebatemaintenance-of-international-peace-and-security-upholding-the-un-charter/): We note with concern the increasing number of cases where armed force is applied unilaterally, invoking the inherent right of self-defence pursuant to Article 51 of the Charter. These cases and the fact that other UN Member States do not publicly express their legal views on each and every case may not be interpreted as a new State practice or opinio juris 17