Final answer:
An insurgent approach that adapts to different circumstances by using a variety of tactics is known as hybrid warfare or flexible response. It involves a mixture of conventional, irregular, and cyber warfare tactics and encompasses multiple schools of thought in foreign policy.
Step-by-step explanation:
The type of insurgent approach or coalition that may use different tactics at different times, adapting to take advantage of circumstances, is typically referred to as having a hybrid warfare or flexible response strategy. Hybrid warfare is defined as a blend of political, conventional, irregular, and cyberwarfare fronts. The concept of flexible response was advocated during the Kennedy administration as a means to respond to various scales of conflicts with a range of military capabilities and strategies, including counterinsurgency, conventional war, and even nuclear strikes.
Flexible response allows for a dynamic application of different schools of thought to respond to changing global threats and challenges. This multifaceted approach to foreign policy and warfare is exemplified by the use of drone strikes, coalition building, and selective engagement in international affairs. Such methods recognize the complexity of modern international relations and the multiplicity of actors involved, requiring a tailored approach to each unique situation.