Least Restrictive Environment vs. Mainstreaming

The federal special education law does not mention the words "mainstream" or "inclusion." IDEA does require that students with disabilities be educated in the "least restrictive environment." See the post on this blog from June 2, 2008 for more details on this requirement.
Despite the requirements of the law, many folks continue to believe that the law requires inclusion. A recent very good poll falls into this trap. The Hoover Institution survey of public attitudes on education provides a wealth of material. For example, the poll finds that with regard to the No Child Left Behind law, the country is strangely divided: 21% want NCLB renewed as is; 29% want it renewed with minor changes; 27% want it renewed with major changes and 24% don't want it renewed at all. Now that is a lack of consensus! You can read the whole poll report here: http://www.hoover.org/publications/ednext/26380034.html
Concerning children with disabilities, however, the poll is less enlightening. The following is a quote from the Hoover Institution report which implies that mainstreaming is required:

"Mainstreaming the Disabled Approximately 15 percent of the country’s elementary and secondary school population have been classified as needing special education, which is partially supported by federal funding under the Individuals with Disabilities Education Act (IDEA).Diagnoses can range from minor learning problems to autism and severe mental retardation to a range of emotional and behavioral disabilities. Whatever the disability, the law mandates that a disabled student be educated in the “least restrictive environment,” a phrase that implies differential treatment depending on the disability, but increasingly has come to mean the “mainstreaming” in standard classrooms of all but those with the most severe disabilities. According to the U.S. Department of Education, the share of disabled students considered to be “fully mainstreamed” has risen from a little more than 30 percent in 1989 to over 55 percent in 2005. Between 1995 and 2005, the share of “emotionally disturbed children” who spend more than 80 percent of their time in a regular classroom jumped from 17 to 35 percent. Neither teachers nor the public as a whole express much support for the practice of mainstreaming emotionally or behaviorally disabled children. When asked whether students “who have been diagnosed with emotional and behavioral disabilities should be taught in regular classrooms with other students,” only 25 percent of teachers, and 28 percent of the public, favor the idea. The rest say they should be “taught in separate settings instead” (Q. 15).
15. Some people say that students who have been diagnosed with emotional and behavioral disabilities should be taught in regular classrooms with other students. Other people say that these students should be taught in separate settings at the school. What do you think should be done with students with emotional and behavioral disabilities?"
In answer to this question, 28% of the nation said regular classroom to 72% separate settings. All racial and ethnic groups and teachers gave similar answers. My problem is the preface.