This chapter shows that attempts to liberalize restrictions on the use of force in counterterrorism operations should be rejected not only on legal grounds, but also as contrary to our national security interest. An increasing number of empirical studies show that more force, particularly in the form of airstrikes, increases terrorist violence and recruitment while increasing popular support for terrorist groups. A restrictive approach to the law governing the use of force against terrorist threats is thus the most effective way to address the reality of those threats. Contrary to the view that international humanitarian law (IHL) is the only source of restrictions on the use of force in counterterrorism operations, the chapter argues that international human rights law (IHRL) can impose additional restrictions on the use of force, particularly when force is used in civilian populated areas away from active combat. Following the jurisprudence of international courts on the application of IHL and IHRL to armed conflict, the chapter puts forward seven factors that should be analyzed to determine the relative application of IHL and IHRL to the use of force in counterterrorism operations. A determination of whether an armed conflict exists is just the first step in determining what kind of force may be used. It is also necessary to consider the circumstances in which force will be used and the reliability of the information on which a strike is predicated to determine the law properly governing the operation.