International law plays a critical role in defining state actions by establishing norms and regulations that govern interactions between states. It aims to promote peaceful coexistence, manage conflicts, and ensure accountability for actions such as human rights violations and aggression. Treaties, conventions, and customary laws shape state behavior and provide a framework for resolving disputes. States are expected to adhere to these laws, although enforcement mechanisms can be weak. Thus, international law functions both as a guiding principle and a regulatory framework in international relations, influencing how states act and interact on the global stage.