In addition to personal attributes and attitudes, there are political factors that might influence the behavior of individuals. As Wilson (1989: 13) wrote, "The freedom of action of bureaucrats is importantly constrained, and sometimes wholly determined, by the decisions of their political superiors." This is borne out in the literature about political control of the bureaucracy where it is shown that appointment decisions made by Congress and the president are influential in directing agency behavior, though this influence is not always in the anticipated direction (Wood 1988; see also Chapter 5 of this volume). Waterman, Rouse, and Wright (1994) found that NPDES personnel attribute substantial influence over their actions to political actors such as federal courts, Congress, and interest groups.