There seems to be no answer to the problems of Northern Ireland, and acts of terrorism and incidents of political violence occur across Europe and the rest of the world with increased frequency. Nationalism in its most disturbing forms menaces peace and security in many countries and communities, and new democracies seems not to have succeeded in reducing State terror. The foundations of the modern state are continually threatened. Terrorism, Security and Nationality shows how the ideas and techniques of political philosophy can be applied to the practical problems of terrorism, State violence and national identity. In doing so it clarifies a wide range of issues in applied political philosophy including the ethics of war; theories of state and nation; the relationship between communities and nationalisms; human rights and national security. Paul Gilbert identifies the conflicting conceptions of civil strife held by different political communities and investigates notions of terrorism both as unjust war and as political crime, considering possible reasons for violent action and assessing their plausibility from a philosophical standpoint. He also provides a much needed philosophical critique of differing forms of nationalism and national identity and concludes by considering the proper response of the State to political violence.