By 1977, The Arc US was arguing that most, but not all, of the options along the continuum of least restrictive environments should be included in the regular school:

Children interacting
Photo courtesy William Bronston, M.D.
  • The least restrictive environment for a child [with mild disabilities] might be the regular classroom. The majority of his educational programming could be conducted in this setting, with some specialized instruction coming from other professionals… In most cases these specialists can train the regular teacher to carry out the entire program…
  • For a student [with severe disabilities], the most normal environment possible might be a self-contained classroom within a school that serves children [without disabilities]. This type of arrangement would allow the individual to receive the highly structured instruction necessary for his progress, while still allowing him to be exposed to children [without disabilities].
  • Some children [with profound disabilities] may have problems so crippling that they are medically unable to attend classes in the traditional school setting because the trip to school endangers their lives.