Legal basis under international law for the use of the Coalition Forces against Islamic State on the territory of Syria

Abstract

This article explores the legal basis for the use of military force against Islamic State on the territory of Syria. The author examines three possible justifications for the U.S. led operation, namely: intervention by invitation of the Syrian authorities, Security Council authorization for the use of force and the right to self-defence. As a consequence of detailed analysis, the author comes to the conclusion that the first two arguments are difficult to sustain. The most persuasive position seems to be that based on the right to individual and collective self-defence. This justification, however, requires a very careful analysis of conditions governing the exercise of the right to self-defence, which, taking into account the specificity of terrorist activities, sometimes may hinder the proper evaluation. This is evidenced by the fact, that not all states taking part in the air campaign against ISIS in Syria, are able to give a plausible justification for their action, allegedly based on the right to self-defence.