CHICAGO, JAN. 9 -- The Illinois General Assembly has granted Mayor Richard M. Daley (D) broad appointive authority over local school councils in an 11th-hour attempt to save the city's landmark School Reform Act that was ruled unconstitutional.

On Nov. 30, the Illinois Supreme Court invalidated the way local school councils are elected. This jeopardized efforts to remedy what former education secretary William J. Bennett called "the worst public schools in America."

Two days ago, Daley and other Democratic leaders agreed with reformers on a compromise bill allowing him to reappoint all 15 members of the Chicago Board of Education and nearly 6,000 elected members of local school councils. The legislation also reaffirmed and validated actions by local school councils before the court decision.

The General Assembly approved the measure late Tuesday on the last night of its fall session. The bill is effective until October when new council elections are scheduled and gives legislators until July 1 to revise the election process. Gov. James R. Thompson (R) said he will sign the legislation before leaving office Monday.

In compromising, reformers gave up hope of immediate passage of a broader measure to make the election process constitutional. That is to be placed on a crowded agenda of the legislature's spring session, which began today and is to last until June 30.

Under the reform act, the 11-member school councils consist of six parents, two teachers, two community representatives and one nonvoting principal, all of whom are elected only by their peer group. The court ruled that the process violates the Supreme Court's one-person, one-vote ruling because parents have more votes than community members.

Although Daley insisted that the legislative delay "is not the end of school reform in Chicago," reform advocates interpreted the action as a major crisis.

"This puts a cloud over local school councils," said Joan Jeter Slay, director of Designs for Changes, a leading school reform group.

"We're looking at a three- to four-month delay that could hold up progress in schools. Do you think that teachers or principals are going to want to sign a contract if the solution still isn't resolved?" she said, adding that half of the councils must select principals under four-year contracts this year.

The act sought to turn decision-making power away from the school board and localize it in each of the city's 547 elementary, middle and high schools with councils on the theory that the local community has a better understanding of what was needed in its schools.

Reformers expressed concern that the legislative disruptions would throw the reform effort back into the hands of politicians.