Whether international law allows preemptive use of military force? ; Ar karinės jėgos naudojimas pateisinamas preventyviąja savigyna?
This master thesis provides an analysis of the legality of preemptive self-defence under international law. In assessing the lawfulness of preemptive self-defence two basic sources of international law: customary and treaty law are examined. The analysis of the UN Charter rules showed that there is strong disagreement between scholars regarding the legality of anticipatory self-defence. However, the term "armed attack" in article 51 UN Charter should embrace imminent threats. Two basic reasons are: the advent of weapons of mass destruction (WMD) and new methods of warfare; the inherent right of anticipatory self-defence was not exhausted after the adoption of the UN Charter. The examination of customary international law showed that the Caroline doctrine allows states to act in anticipation of an armed attack if the requirements of necessity and proportionality are fulfilled. In addition, the analysis of state practice and opinion juris prior and after September 11, 2001, revealed that anticipatory self-defence is not prohibited. The conclusion is maid that the right of anticipatory self-defence, if requirements of necessity and proportionality are fulfilled, is not illegal under international law. In contrast, the analysis of the UN Charter rules showed that preemptive self-defence against perceived threats is not legal under the UN Charter, because there is no actual armed attack or imminent threat against which state can legally defend itself. In addition, preemptive use of military force against emerging threats has no safeguards. The examination of customary law prior and after September 11, 2001, revealed that a new rule, which would allow states to use military force in self-defence, was not created, because there is a lack of opinio juris and state practice. The conclusion is drawn that preemptive use of force is not legal under international law.