"Military defense is based on the idea of deterring aggression, staying operationally ready, and the ability to meet all kinds of challenges including non-conventional threats such as terrorist bombings, hijackings, and chemical, biological, and radiological attacks" (Siddiqi, 196).
The idea is to always be ready for war due to threats being inevitable and something that a state should always prepare for
"For Morgenthau, just as for Thucydides and Hobbes, international politics is best characterized as a struggle for power. In this context, both military and economic power matter. Economic power can be used for coercion, in and of itself, and can also be translated into military power, if needed. Both types of power are therefore sought by states in order to protect themselves" (M-EM, 72).