The United States Joint Forces Command (JFCOM) has the requirement to conduct joint experimentation for the Department of Defense. Joint experiments are conducted for many purposes: examine new warfighting concepts, determine the impact of new technology, assist in the development of new procedures, and study a specific type of joint combat or stability operation. A major shortcoming in previous experiments conducted by JFCOM has been the inability to model the political, economic, diplomatic, cultural, social, religious, psychological, informational, and infrastructure issues associated with modern warfare. For several years, JFCOM has been searching for a tool with the potential to model these critical areas of Effects-Based Operations, and also be used to bring members of the inter-agency groups into JFCOM experiments in a realistic, timely and cost effective manner. A recent prototype event demonstrated modeling at an unprecedented level of a granularity. The Krannert Graduate School of Business at Purdue University developed and modified for use the SEAS (Synthetic Environment for Analysis Simulation) simulation engine. SEAS is an agent-based simulation that models populations at varying levels of abstraction by portraying: environments, artificial agents, and the interactions among environments and agents. Human players dynamically try to influence the behaviors of the simulated agents, in keeping with their player defined strategy, as both players and agents respond to the confrontational dilemmas that the simulation facilitates. This paper will outline the reasons why a simulation like SEAS is so important to joint experimentation today. It will discuss how SEAS was used in a recent prototype demonstration conducted by JFCOM and address the potential for future use at JFCOM and the military services. The academic theoretical underpinnings of SEAS will be described, as will the composition and functioning of the intelligent agents used to represent the groups and organizations modeled in SEAS.