State's response to an armed attack carried out by non-state actor : remarks on example of 'unwilling or unable' doctrine

The aim of the article is to point what the doctrine 'unwilling or unable' is about and to find an answer to the question about legal means, which can be used by states to fight e.g. with terrorist groups. The first part of the article focuses on the characteristic of the doctrine, examples of its application and justification, as well as on pointing the doubts concerning the conditions of its application. In the second part, the self-defense and state's responsibility for internationally wrongful acts were discussed, as alternative, legal means, which can be used by states facing the threat for their security.