David Easton was the first person to apply systems theory to the field of political science. In doing so, he introduced an innovative and holistic approach to the study of politics. In his groundbreaking book, "A Framework for Political Analysis," published in 1965, he defined politics as the "authoritative allocation of value," a definition which has framed the study of politics ever since.
Easton was the first social scientist to study politics as its own system rather than as a segment of a greater social system. He analyzed politics as an always-changing set of processes that people use to change and control their environment.
Easton posited that in a stable political environment, when something changes socially or physically, people either support the change or demand a return to the status quo. Competition arises out of these differing opinions regarding the change. When a policy is established, it interacts with the changing situation to produce further changes. The outcomes of the enactment of the policy in turn produce more changes, which people in turn support or oppose. This new level of support or opposition causes the political process to turn back to the beginning of the cycle, which then repeats ad infinitum.