In the controversy surrounding the forced resignation of rehabilitation services Commissioner Justin Dart Jr. from the Education Department this month, the sharpest contention has been over charges of mismanagement leveled by Dart and his supporters against Madeleine Will, assistant secretary for special education and rehabilitative services. But the acrimony stems at least in part from a more difficult and longstanding disagreement among advocates for the disabled.

The disagreement is, on one level, a routine contest for funding from a limited pot of money -- in this case, vocational rehabilitation funds for job training, with advocates for severely handicapped persons pitted against an older constituency of persons with less severe handicaps.

But there is, on a second level, the complex question of whether and how a program that has successfully trained and helped employ the less handicapped should be opened up, without a large infusion of new funds, to the profoundly mentally retarded and other severely disabled persons, who require more training and ongoing support to stay in jobs.

"The issue is competition over frozen resources . . . a classic struggle between an older constituency and a newer constituency," said a House aide who has worked on the issue.

Dart, son of the late Justin Dart, California businessman and member of President Reagan's first "kitchen cabinet," was asked to resign after he scrapped his prepared testimony and publicly criticized the Education Department before a House subcommittee Nov. 18. At the hearing, he complained that the office headed by Will was plagued by "profound problems in areas such as management, personnel and resource utilization" and was "ravaged by disunity and hostility internally."

It was these problems, not a policy disagreement over services for the severely handicapped, that led to his firing and disunity among advocacy groups, maintains Dart, a polio victim who uses a wheelchair. But Will argues that resistance to serving the severely handicapped from those who provide rehabilitation services -- led by state rehabilitation directors -- "is the issue . . . . This was the issue between them and the federal government."

While the two sides disagree about what was the immediate cause of Dart's departure -- Dart supporters contend that Will is painting the conflict as a policy debate to deflect attention from their complaints about poor management -- the debate over job training programs remains unresolved.

Running through the arguments are delicate questions about who is most deserving of federal rehabilitation services, or, as one advocate put it: deciding "whether a Harvard MBA who suffered a disability and is in a wheelchair has something in common with someone who has an IQ of 60." Both camps

imply that the other is making a decision that one category of the disabled is more deserving than the oth- er.

The extreme positions can be set out this way:

Advocates for the most severely disabled, including Will, argue that persons with brain trauma or serious mental retardation, for example, should be given as much opportunity to be trained for employment as those who may be trained with less effort, the blind or deaf, for example. The more severely handicapped, until recently, have not applied for or been considered eligible for job training under the federal program.

Expanding vocational rehabilitation to the severely handicapped entails ongoing services known as "supported employment," often including provision of a "job coach" who will work on the job with the handicapped person, transportation services or other help that would not be necessary for a less handicapped person.

At the other end of the conflict are advocates for those with less severe handicaps. The 60-year-old vocational rehabilitation program has traditionally served this clientele: persons deemed capable of training for "competitive employment," marketplace jobs they can hold without continuing help from a rehabilitation program.

Vocational rehabilitation directors at the state level -- whose programs receive 80 percent of their funding from the federal government -- argue that they are supportive of expanded services for the severely handicapped. But they have also strongly maintained that, without new funding, they cannot provide training for the severely handicapped without pulling services away from their traditional clients.

"I'm not trying to paint it like it's black and white," said Dart. "I detect a great desire {among state agencies} to serve the severely disabled. But they feel they have to have resources to train the people and provide the services."

In part, the issue has risen naturally, as medical and technological advances have extended the lives of severely handicapped persons, who in the past commonly died young. Also, the decade-old federal law guaranteeing a public school education for handicapped children has provided educational and therapeutic services that have brought seriously disabled persons into mainstream society. As these children complete school, there is an increasing demand for vocational training.

"In the past four years, the most important question this administration has dealt with in terms of the rehabilitation issue is whether we can pry open the door to the rehabilitation system to allow the inclusion of the more handicapped people," said Will, who has a son with Down's syndrome. "The {federal law covering rehabilitation} is not specifically designated for a certain part of the disabled community."

Will, who is supported by organizations including the Association of Retarded Citizens and The Association for Persons with Severe Disabilities, contends that the state agencies that provide job training "view supported employment and the request to expand services to this population as very threatening."

The state directors bristle at the suggestion that they do not want to serve this group, pointing to figures showing that 62 percent of their clients -- compared to 47 percent a decade ago -- are severely handicapped under the definition contained in the federal rehabilitation law. Will argues that the definition is too broad, with states often excluding those she considers severely disabled.

Some state directors also contend that, while they are attempting to serve a range of disabilities with limited resources, Will has focused her energy and discretionary funding on supported employment to the detriment of other programs.

Paul Dziedzic, president of the Council of State Administrators of Vocational Rehabilitation, said the states can document that they are providing services to the severely handicapped in supported employment. "We also feel very accountable to the needs of many disabled people for whom supported employment is not appropriate," he said. "What we say is don't lose sight of the whole picture in focusing on a part of the picture."

The tension over the issue emerged during legislative battles last year, when advocates fought over whether to require states to use their federal grants for supported employment.

"Some of us argued that yes, we wanted to help if we could place {the severely handicapped} into competitive employment," said a Senate aide who asked not to be named. "But saying this is a whole new group . . . and pushing a whole category of people out, it was a trade-off . . . . It would have been changing the whole nature of the program."

The legislation was passed with a compromise that created a separate $25 million program for supported employment, out of a total $1.5 billion rehabilitation program budget.

While Dart has been a vocal critic, he nevertheless says he admires Will, calling her "one of my heroes . . . a tenacious advocate." He said he believes that the debate must be aired, but that he is deeply troubled by the "tragic" disunity among the advocacy groups.

Others who work in programs for the disabled are also nervous about the rift that has grown over the resource issue.

"It's still there. It needs to be solved," said an official of one advocacy group. "You can't maximize the effort to improve the lives of persons with disabilities without a total effort . . . . The division is very unfortunate and counterproductive."