Studying non-state actors in international security research can be a daunting challenge. So much so that it takes a whole book, such as this one, to discuss all the potential research strategies. This area of research is difficult for many reasons, and these reasons can be related to methodology (eg sampling, collection and analysis of data), theory (eg competing paradigms–see Walt 1998: 38), and conception and definition.

This chapter illustrates issues of conceptualization based on the question of how to conceptualize terrorists–who represent a particular type of non-state actors–and, more specifically, how to conceptualize their violent actions. In social research, one has different options for operationalizing terrorism and political violence, each of which has its own methodological, theoretical and conceptual advantages and flaws. The goal of this chapter is to enable the researcher to make a conscious decision about which approach is most suitable and to explain how one can operationalize particular research objectives when studying nonstate actors in the realm of international security. As the most prevalent form of violent conflict today, clashes between nonstate actors, as well as between non-state and state actors, have replaced the classic inter-state wars of the 20th century (Kearns and Young 2014: 256). Almost every contemporary armed conflict involves a wide range of participants, including private military and security companies (PMSCs)(see Chapter 4 by Magnus Dau and Marlen Martin, Chapter 6 by Joakim Berndtsson and Chapter 8 by Andreas Kruck), private militias, rebels (see Chapter 3 by Alexander Spencer), defected battalions, pirates, warlords, organized criminal gangs, cartels, insurgents, self-proclaimed states and pro-this or anti-that groups.‘Classic’geopolitical disputes, such as the South China Sea, and inter-state wars, such as the conflict between Russia and Georgia in 2008, seem to be the last of their kind.