5 The use of force against terrorism: a new war for a new century?
- Terrorism — Self-defence
This chapter examines the impact of the ‘war against terror’ on international law. The US invasion of Afghanistan in response to the massive terrorist attacks on the World Trade Center and the Pentagon on 11 September 2001 led to a fundamental reappraisal of the law of self-defence. The US response to 9/11 was to announce ‘a different kind of war against a different kind of enemy’—a global war on terrorism. Many writers now argue that 9/11 and subsequent state practice have changed the law on self-defence, but the legal situation is not so clear-cut. More recently, the rise of ISIS in Iraq and Syria, and the military response by the USA and other states since 2014, have given rise to renewed debate about the scope of self-defence. And President Trump’s foreign policy with regard to North Korea and Iran has once again raised questions about the controversial doctrine of pre-emptive self-defence.