A civil war is raging in the State of Mesopotamia between a repressive government led by Colonel Recip and armed opposition forces who seek the overthrow of the government so that they can take control of the rich resources of Mesopotamia. Goko Baram, a terrorist group, takes advantage of the chaos during the conflict, and seizes large areas of territory. It proclaims a Caliphate over large areas of Mesopotamia and the neighbouring State, Akad. Members of Goko Baram fire rockets into Akad. They also threaten to carry out small-scale terrorist attacks in the powerful State of Tianzhu because it has supported Colonel Recip for many years. The UN Security Council authorizes the use of 'all necessary means' to protect the civilians of Mesopotamia from threat of attack. Tianzhu relies on this authorization to attack government forces and to overthrow the regime. Tianzhu continues to carry out large-scale air strikes against the Goko Baram terrorist group in Mesopotamia, saying that it is acting in collective self-defence of Akad. However, Akad has good relations with Colonel Recip and it calls on Tianzhu to cease its actions. Tianzhu then carries out drone attacks on the leaders of Goko Baram in Mesopotamia, saying that it is acting in self-defence against imminent attacks against its nationals in its own territory. Advise Tianzhu whether its use of force is lawful. The candidates were expected to identify and apply different claims for the use of force, from acting under UN Security Council authorisation under Chapter VII (reflecting on the meaning of the term 'all necessary means' in light of Resolutions 678 and 1973 in the contexts of Iraq, Libya and Syria), through the conditions of collective self-defence under Article 51 UN (whether an armed attack by non-state actors amounts to an attack and the conditions for collective self-defence) and finally claims about anticipatory and pre-emptive self defence. Good answers discussed the doctrinal debate on the interpretation of Article 51 UN Charter, reflected on the tests defined in ICJ cases such as Nicaragua, DRC v Uganda, and considered state practice in the aftermath of 9/11 (including US SD Legal Adviser Brian Egan's speech setting out a very wide doctrine of counter-terrorism and the unwilling or unable doctrine). Following a period of social unrest and deep economic recession, the regional authorities of Arkam, a province of Rantania, organised a referendum on Arkam's secession from Rantania. Three-quarters of the electorate participated in the referendum, which resulted in a 65% 'yes' vote in favour of secession. Five days after the referendum, the regional authorities of Arkam issued a unilateral declaration of independence.
Anticipating fierce opposition by the central government of Rantania, the regional authorities of Arkam asked the government of Marcelux, a highly militarised neighbour, for their support in establishing the new state. Marcelux complied with the request and deployed troops in strategic places in the territory of Arkam with a view to 'keeping the peace'. The central government of Rantania protested vehemently against the 'flagrant illegality' of Marcelux's actions, but