Montgomery County School Superintendent Charles M. Bernardo, whose new contract was voided by a court ruling Thursday, declared yesterday that he was being made a scapegoat by people in Montgomery "who are unwilling and unable" to make hard political choices in an era of change.

Denouncing the "catchall phrases" such as "runaway budgets" and "burgeoning bureaucracies" which his critics use to describe his administration, the 41-year old superintendent reiterated his intention to stay on the job while he appeals the court ruling.

During a two-hour interview yesterday Bernardo attacked what he calls "regressive attitudes" in Montgomery that "labor under the illusion" that the country remain homogeneous. He also called the court ruling "shabby."

It was the first time the normally imperturbable Bernardo has taken the offensive since the ruling, which invalidated the superintendent's second four-year contract, which was granted last June by a previous school board.

The ruling stipulates that the board must appoint in interim superintendent next October when Bernardo's first contract expires.

The decision was a triumph for the board's conservative majority, which filed the circuit court suit seeking the contract invalidation. Bernardo, these board members said, alienated parents and teachers by closing 23 county schools with declining enrollments and reorganizing the school bureaucracy.

Yesterday, Bernardo attacked his critics, saying the changes he brought to the county school system were urgently required by declining enrollments, shrinking funds and the county's increasing diversity.

"I brought aggressive and skillful leadership to this school system," he said, "but it seems that only mediocre leadership has a chance to survive here very long."

Bernardo said he remembered telling the school board four years ago, when he was first hired, how thirlled he was at the prospect of meeting the challenge of an increasingly diverse population-including backs, Hispanics, the underprivileged and the handicapped-while maintaining the county standard of high test scores.

But Montgomery County, he said, "is not as sophisticated as people believe" when it comes to making necessary compromises.

"There is an island perspective that, dominates this country," he said. "Montgomery isn't as much a community as it is a series of islands with varying interests and degrees of myopia.

In the school business it takes the form of people saying to me I don't give a damn about programs in other schools. I want . . . then they list their demands for their own schools."

"In other places considered less sophisticated than this I've found that people can get angry but will in the end reach decisions for overall policy in their system," he said. "(Here" few people want countrywide policies. They care only for their particular island."

When Bernardo arrived in Montgomery in 1975, he said, the school board - then a more liberal group - gave him a very specific series of goals which he believes he fulfilled.

"The board wanted peace between labor and management," he said. "So I helped put together an unprecedented three-year contract for teachers.

He said he helped expand bilingual programs and educational services for the handicapped, while instituting an innovative computer-assisted program in basic skills.

While conservative board members describe that program as a burden to teachers, Bernardo protested that it was an ideal and successful effort to meet the back-to-basics philosophy.

Bernardo defended the school closings as "absolutely necessary" and pointed to his creation of middle schools as a way to meet the enrollment decline while, maintaining "educational excellence."

He is proud, he said, of his establishment of special centers for gifted and talented students, and alternative schools where students learn to refurbish automobiles and build houses.

Finally, he defended his record in human relations, including the mandatory course in black studies for school employees, which the board made optional earlier this year.

"For the first time," he said, "special groups like racial minorities and the handicapped feel they have a stake in this system."

Bernardo said the fundamental philosophical difference between him and the four-member board majority centers on their views of the county. While he sees the county as racially and economically diverse, Bernardo said, the conservatives view it as homogeneous.

Referring to the board majority he said, "Undue reliance on the single text approach and the teacher at the head of the class imparting information is based on an assumption that all youngsters should be learning the same way."

"That is a false assumption, especially in a county that is changing as rapidly as this one."

"We talk about the necessity to be a more responsive school system, yet we labor under the myth that all of these varied needs can be met by traditional methodologies," he said.

Bernardo said he was confident the state court of appeals will reverse decision by the lower court, which reflects, he said, "its attraction to the political moment."

If you try to caccommodate everyone for the sake of immediate gain without gain without having an idea of overall perspective and policy, you run the risk of doing nothing," he said. "That I will not do. Nor will I be a puppet in the interest of personal security."