What is the difference between a “disaster” and an “emergency”? One can safely say that for the victim of an event, it is always a disaster. But what about the first responders who are tasked with returning conditions to normal as quickly as possible? What about the executives who must direct the first responders, as well as coordinate resources? The difference is a “matter of degree” because it depends on the amount of resources that are required to respond to the incident. For example, an overturned gasoline tanker truck may only be an emergency for a major metropolitan area, but a disaster in a more rural region. American public safety is a mirror image of the government system of federalism that developed during the founding of the United States. Public safety entities are attached to the various local, state, and federal government agencies. There are almost 18,000 local law enforcement agencies across the US. Only 47 agencies have more than 1,000 sworn officers, while almost 90 percent have less than 50. There are more than 30,000 fire departments, yet only about one-quarter of all firefighters are full-time professionals. The rest are volunteers. The author, a 30-year law enforcement veteran, has developed a college-level course for public safety executives to help them understand the “matter of degree.” The intent of the course is to challenge executives to conduct a careful self-examination of their own public safety agencies to determine what they are capable of doing in an event. An executive only gets one chance to do it right, so being able to distinguish between a disaster and an emergency response will be critical to success. When the event occurs, a public safety executive will be better prepared to make key decisions.