“We have defeated ISIS in Syria”, US President Trump, tweeted on 19 December 2018. “We just took over 100% caliphate. That means the area of the land.”, he added in March 2019. Nonetheless, until to date, the global coalition against the “Islamic State of Iraq and the Levant” (ISIL) continues its military operations in Iraq and Syria. May States in Syria still use armed force against ISIL, now deprived of territorial control, under the right of (collective) self-defense?
The German Government answered this question in the affirmative. On 18 September 2019, the Government formally requested the German Parliament to extend the (national) mandate “for German armed forces to safeguard the stabilization of Iraq and Syria, to promote their reconciliation, and to prevent ISIL’s regaining of strength in those regions” (all translations by the author). The Parliament is currently debating the issue. With the governing parties endorsing the request, Parliament is expected to agree despite critique on the operation’s legality by opposition parties.
In its formal request, the Government details the legal basis for the continuation of operations against ISIL. As a matter of principle, it does not significantly depart from its previous justifications. It bases the use of armed forces in Iraq on the “Iraqi government’s continuously valid request and continued consent”. For its operations in Syria, the Government continues to invoke collective self-defense on behalf and on request of Iraq against attacks from ISIL, “in connection with” Security Council resolution 2249 (2015).
But importantly, the Government has also updated its justification in light of ISIL’s loss of territorial control. This, in short, would not affect the coalition’s right to continue military operations against ISIL in Syria. This updated justification is worth discussing in regard to three aspects of self-defense: whether it can be used against non-State actors, its endorsement by the Security Council, and the question of continuing armed attacks.