This study examines the proposed and utilized decision-making processes of an interagency taskforce formed to create a strategic plan for addressing substance abuse concerns. Analysis of data obtained through prolonged observation, interviews, and document collection indicated that, although the planned structure remained relatively intact, the taskforce deviated from planned decision-making processes in the procedures and decision-making criteria utilized. These deviations were justified through retrospective rationality and strategic ambiguity. Although prior research has described decision making using rational, satisficing, and garbage can models, the theoretical implications of this study point to a renewed understanding of collaborative decision making combining these approaches. Ultimately, this study illustrates how the characteristics of a loosely coupled, bona fide interorganizational group both enabled and constrained the decision-making process. Accordingly, practitioners and scholars alike should consider the advantages and limitations of retrospective rationality and strategic ambiguity across a variety of group and organizational contexts.