In this article we discuss the definition of emotionally disturbed (ED) from the Individuals with Disabilities Education Act, with a specific focus on the clause contained in this definition, which is designed to exclude from special education services students who are considered to be socially maladjusted (SM). The history of the SM exclusionary clause and its impact is detailed herein. We argue that the federal ED definition, and especially its SM exclusionary clause, have both served to inhibit the progress of the behavior disorders subspecialty within the special education field, and have diverted energy and attention from more important aspects of serving students with behavioral and emotional problems. From both a pragmatic and empirical standpoint, we argue that the SM exclusionary clause is untenable, and that it deserves neither our support nor the continued professional focus that it continues to demand. Using the "Triangle of Support" model as an exemplar, we propose that assessment methods should be linked to comprehensive systems of service delivery to provide a true cascade of services for students with behavioral and emotional problems. Recommended alternative definitions of ED are discussed, including the National Coalition definition of Emotional and Behavioral Disorders that narrowly missed congressional approval for replacing the current definition. Further, we recommend adoption of the externalizing-internalizing broadband dimensional dichotomy as an emerging and scientifically sound alternative way of conceptualizing emotional and behavioral problems.