System-based research remains an important yet usually outdated and internally contradictory approach in political science and international relations. Based on concepts borrowed from physiology, cybernetics, and general system theory, the system-based approach popularised in the 1960s was cast away as outdated and ill-focused. Despite those systems, the theory was developed in natural sciences, eventually creating a paradigm more applicable to domestic and international politics. The weakest element of past systems (like the one proposed by D. Easton) was that they did not allow for a sudden and catastrophic transformation and lacked emergence. This paper aims to present a model that would allow for the system’s ordinary and catastrophic transformation. The complex adaptive system features were defined using relevant literature on a paradigm of complexity. Connecting it with the propositions of D. Easton, R. Axelrod, and M. Cohen, as well as R. Jervis, such a model was constructed. The theoretical introduction is supplanted with a general case study of the early phases of the Arab Spring in Tunisia. The model mirrors the complex systems’ dynamics, considering the agent-structure problem.