Abstract: Information systems for crisis response and management, including military Command & Control systems, are designed to support their users' decision-making processes. Decision making can be rational or naturalistic. Psychologists have shown that experienced decision makers under time pressure prefer using naturalistic methods. Case studies of four implemented Command & Control systems show that most decision support assumes rational decision making. Some support for naturalistic decision making is becoming available. We identify a mix of rational and naturalistic decision support tools as being desirable for flexible Command & Control.