The conventional wisdom is that counter-terrorism (CT) involves a “whole of government” or “holistic” approach. Each government department plays a role in a comprehensive strategy that incorporates security measures, but also economic, legal, political and informational initiatives. While this is true, it is the security services that continue to play the lead, active role in CT, particularly at the operational and tactical levels. The security sector incorporates many different agencies and institutions, which can include the armed forces, police, paramilitary forces, intelligence agencies, border security, governmental oversight bodies, the judiciary and correctional systems, non-state security bodies, and civil society organizations. All of these agencies have a part to play in CT, but the focus of this chapter is on the main actors – the armed forces, the police and the intelligence services.
Although this chapter addresses the three elements separately, it is evident that contemporary CT operations have fostered interagency cooperation and coordination on an unprecedented scale, resulting in considerable overlap between the roles of the intelligence, law enforcement and the military. The previously well-defined roles of these services have largely disappeared in the last decades as CT operations have become more urgent, complex and transnational. The demands of contemporary CT have also resulted in significant changes to size, composition and roles of all of these agencies.