In this ICCT Research Paper, Dr. Christophe Paulussen explores whether the current international legal framework is sufficiently equipped to effectively deal with the threat of terrorism and counter-terrorism practices or whether it is in need of change. The paper specifically looks at whether the current jus ad bellum (the law regulating when inter-state force may be used) and jus in bello (the law of war, the law regulating the conduct of warfare) are still suitable in the current climate. This Paper clarifies a few concepts that are often heard, and sometimes misunderstood, in the counter-terrorism discussion: counter-insurgency (and then in particular its correlation with counter-terrorism) and asymmetrical warfare. The final section offers some concluding remarks.