The formal invocation and benediction at the University of Idaho commencement will be replaced next spring by a moment of silence, school officials say.

But it appears Grangeville-area school patrons do not support the American Civil Liberties Union call for a separation of church and state in their north-central Idaho classrooms.UI President Elisabeth Zinser agreed to follow the recommendation of the Faculty Commencement Committee to drop the official prayer at graduation. In its place will be a "sustained moment of silence."

The change came after more than a year of study by the committee. The ACLU of Idaho raised the possibility of filing suit last month against the UI to stop the practice of prayer.

In reaction to the move, Alan Kofoed, president of the ACLU's Idaho chapter, said case law on the subject is "not absolutely clear." But, he said, "it sounds like they're getting up a moment of silence as a vacuum for prayer," and he opposes that.

Zinser said the change to drop the long-standing practice of prayer was made in recognition of the multireligious and multiracial makeup of the university.

"For the graduation ceremony to be meaningful for everyone, the ceremony must recognize the different backgrounds and beliefs of all who attend," Zinser said in a memo.

The new plan will go into effect May 18, 1991.

Kofoed, meanwhile, said he does not want to sue his hometown school district, but lately has been considering it.

The Grangeville School Board recently said it will not stop prayers at commencement ceremonies until it receives a court order.

"That can be arranged," Kofoed said Wednesday night during a speech before 25 civil libertarians at the University of Idaho. "If we have to go to court, we will . . . Perhaps reason will prevail."

He said most people in Grangeville disagree with prayers at official school functions, but the school district is run by what he called a dogmatic few who are intruding on individual rights.

"I was shocked and amazed to find my hometown on the front pages of the newspaper in Boise," Kofoed said.

But on an ACLU fact-finding mission to Grangeville Thursday, Kofoed found religion is a lot more popular there than his group.

More than 100 people crowded into the City Council chambers to stick up for God and to tell ACLU representatives they were way out of line for trying to get God out of the public schools.