International Law and the Use of Force

The questions that arise from the use of force are amongst the most controversial both in international law and international relations. Different states, civil society and international lawyers have held over time diverse opinions about the legality and the legitimacy of events such as Russia’s invasion of Ukraine in 2022, the bombing of Iraq and Syria (by the US, UK, France, Australia and others) in the war against the ‘Islamic State’ and affiliates, the use of drone strikes globally in the ‘War on Terror’ since 2001, the exercise of the 'responsibility to protect’ by the ‘international community’ in Libya in 2011 and the 2003 invasion of Iraq, as well as debates over the possibility of a 'pre-emptive strike’ against North Korea or Iran. The question of what amounts to ‘force’ has also been contested by States since at least 1945, and the emergence of new technologies of warfare have reinvigorated these debates. Finally, the question of what to do about the unlawful use of force (including criminal and economic sanctions) has been the focus of renewed attention since Russia’s invasion of Ukraine and annexation of Crimea.