This study develops a framework for the design of a Joint Simulation, Analysis, and Wargaming Center (JSAWC). JSAWC is proposed as the primary decision support center for the Turkish General Staff. The complexity of warfare systems and the fog of future wars make military planning, problem solving, and decision making processes difficult to accomplish without using computerized analysis support tools. The proposed JSAWC will use modeling and simulation technology to provide analytical support for Turkish military decision-makers and planners in operations planning, force structuring, and training. An iterative systems engineering process is defined and applied to the primary design of the center. After providing a background on modeling and simulation, basic functions of the Turkish Defense System are analyzed to identify appropriate missions, users, and environment of the JSAWC. General needs, constraints, and alterables of the project are identified.