Foreign policy is how a state interacts with other states and international actors. It is influenced by both internal factors like a country's geography, leadership, and public opinion, as well as external factors like the international system and other states. The foreign policy process involves decision making, which can follow rational, organizational, or bargaining models. Individual leaders and groups also influence decisions through psychological biases or pursuing their interests. A country's diplomats, interest groups, public, military, and legislature all shape its foreign policy choices.