This paper aims to draw a series of generalizable conclusions regarding the incident command system (ICS) as a management tool for structuring the activity of disaster response agencies at the site of disasters in the United States. It identifies the basic elements of the system and makes some observations regarding its range of applicability. The analysis is drawn from several sources of information regarding the use of ICS in nine different disasters in which Federal Emergency Management Agency's (FEMA) Urban Search and Rescue (US&R) Taskforces participated. Results suggest the applicability of ICS in a range of emergency response activities, but point to the importance of context as a largely un-examined precondition to effective ICS. Our findings indicate that ICS is a partial solution to the question of how to organize the societal response in the aftermath of disasters; the system is more or less effective depending on specific characteristics of the incident and the organizations in which it is used. It works best when those utilizing it are part of a community, when the demands being responded to are routine to them, and when social and cultural emergence is at a minimum. ICS does not create a universally applicable bureaucratic organization among responders but rather is a mechanism for inter-organizational coordination designed to impose order on certain dimensions of the chaotic organizational environments of disasters. We conclude by extending our observations from the USAR context to the reconstruction, recovery, and mitigation phases of disasters in order to illuminate the general limitations of the approach as an all-encompassing model for disaster-related organizational and inter-organizational functioning and coordination. Our final conclusions suggest that the present-day efforts in the National Incident Management System (NIMS) to use ICS as a comprehensive principle of disaster management probably will not succeed as intended.