Peter Bachrach, 89, formerly of Ardmore and Center City, a professor emeritus of political science at Temple University, died of an apparent stroke Friday at his home in Southwest Harbor, Maine.

Dr. Bachrach, who retired from Temple in 1988, advocated political activism by all segments of society.

"He was a leading theorist of participatory democracy," a Temple colleague, Aryey Botwinick, said. In 1992 Dr. Bachrach and Botwinick coauthored a book, P

ower and Empowerment: A Radical Theory of Participatory Democracy

. The book's premise was that government decisions have an impact on corporations, therefore, people in workplaces should have a say.

Dr. Bachrach was the author of more than 10 books and numerous articles, including the landmark "Two Faces of Power," about the subtle ways power is manifested in America. In the article, published in the review American Political Science in 1967, he coined the word


, to describe how the powerful can keep agendas off the table so no decisions are made. For example, Botwinick said, no decisions about pollution are made if powerful companies lobby to keep it from legislative agendas.

Steven Lukes, who debated with Dr. Bachrach at Oxford University and taught at Temple with him, said, "He influenced many political theorists, including me."

Dr. Bachrach was crippled by a childhood bout of polio and used two canes to walk. There must have been times when he was in pain and uncomfortable, Lukes said, but he always appeared to be full of joy and "lit up a room." He was direct with his students, but he was also kind and considerate, Lukes said.

A native of Winnetka, Ill., Dr. Bachrach earned a bachelor's degree from Reed College in Portland, Ore., and earned a doctorate in political science from Harvard University.

He served on the faculty at Bryn Mawr College for more than 22 years before joining the Temple faculty in 1968. That year, he helped establish a chapter of Students for Democratic Action at the school.

In 1971, he joined with Temple's student senate and threatened court action to demand that the administration open its financial records to justify raising tuitions. He argued that Temple's budget and trustees minutes should be made public so that they could be scrutinized by students and faculty.

Dr. Bachrach ran unsuccessfully in 1969 for president of the American Political Science Association. "He wanted the association to take a stand against the Vietnam War," Botwinick said, "He was radical but in the best possible sense."

Dr. Bachrach and his first wife, Florence Rice Bachrach, raised six children in Ardmore. A friend of the children, Tom Horne, said Dr. Bachrach was "charismatic" with young people. "He would take us seriously, more seriously than our parents did sometimes. You would end up shooting pool with him and having long conversations." Many of the pool shooters ended up in academia, said Horne, who is a professor of political science at the University of Tulsa.

Dr. Bachrach's first wife died in 1975. Since 1976, he had been married to Adrienne A. Bachrach. They lived in Center City before moving to Maine in 1992.

He enjoyed his sailing kayak in Maine, and loved chess and stamp collecting.

In addition to his wife, Dr. Bachrach is survived by daughters Lori, Kate, Sarah, Molly and Ruth; a son, David; stepchildren Alice, Malcolm, Robin and Bill; a sister; and 22 grandchildren.

Services will be private.

Memorial donations may be made to the American Civil Liberties Union, 25 Broad St., 18th Floor, New York, N.Y. 10004.