Critical to the development of unmanned ground vehicle platforms is the incorporation of adaptive tactical behaviors for the planning of high-level navigation and tactical actions. BBN Technologies recently completed a simulation-based project for the Army Research Lab (ARL) in which we applied an evolutionary computation approach to navigating through a terrain to capture flag objectives while faced with one or more mobile enemies. Our Advocates and Critics for Tactical Behaviors (ACTB) system evolves plans for the vehicle that control its movement goals (in the form of waypoints), and its future actions (e.g., pointing cameras). We apply domain-specific, state-dependent genetic operators called advocates that promote specific tactical behaviors (e.g., adapt a plan to stay closer to walls). We define the fitness function as a weighted sum of a number of independent, domain-specific, state-dependent evaluation components called critics. Critics reward plans based upon specific tactical criteria, such as minimizing risk of exposure or time to the flags. Additionally, the ACTB system provides the capability for a human commander to specify the "rules of engagement" under which the vehicle will operate. The rules of engagement determine the planning emphasis required under different tactical situations (e.g., discovery of an enemy), and provide a mechanism for automatically adapting the relative selection probabilities of the advocates, the weights of the critics, and the depth of planning in response to tactical events. The ACTB system demonstrated highly effective performance in a head-to-head testing event, held by ARL, against two competing tactical behavior systems.