Answer:
Ad hoc
Step-by-step explanation:
Adhocracy is a style of organization that is adaptable and flexible and doesn't have a formal structure which allows to use multidisciplinary teams that are organized by functions. This type of organization groups people together to solve a particular problem or develop a specific task.
According to this, the answer is that this style of staff organization is called ad hoc because President Clinton maintained a flexible structure that allowed him to adapt it to include people in certain situations according to the needs.