Final answer:
According to realism, the international system is characterized by states that prioritize their own interests, security, and power, operating in an anarchic international system as rational actors in a zero-sum game, vying for advantageous positioning through a balance of power.
Step-by-step explanation:
According to realist theory, the international system is fundamentally characterized by the notion that states are the principal actors in an inherently anarchic international system. These states are rational actors primarily focused on pursuing their own self-interest, security, and power. Realism posits that states operate with a "go-it-alone" attitude, aiming to ensure their own safety and security by gaining more power, which they use to influence other states and the rules of the international system.
This view suggests that international relations are a zero-sum game, where one state's gain is another's loss, and is often maintained through a balance of power among states. Realists see the system as being divided into poles, or centers of power, with states racing to position themselves advantageously. The concept of polarity can manifest as unipolar, bipolar, or multipolar alignments, with power dynamics shaping the international order.