Former undersecretary of state Lawrence Eagleburger told graduating students of George Washington University yesterday that the world's democracies must act in concert against terrorism or face "very serious threats" to world stability.

Eagleburger, asserting that the United States "crossed the Rubicon" when it attacked Libya recently, drew applause when he said that leaders such as Libyan head of state Muammar Qaddafi must weigh their support of terrorism carefully with the knowledge that American military forces may lash out again.

Qaddafi may continue to sponsor attacks against Americans, Eagleburger said, "but he will do so in much greater doubt about his future on this planet than would have been the case a month ago."

Eagleburger delivered his remarks to a gathering of 170 students of the School of Public and International Affairs and their friends and families. Across the university yesterday, five other commencement ceremonies were held for more than 1,600 undergraduate and graduate students.

Eagleburger, a former career diplomat who is president of the New York consulting firm Kissinger Associates, painted a bleak picture of 20th century global politics and warned that if the United States and its allies do not recapture the spirit of cooperative action, the West will face an epidemic of terror.

Beginning his speech with a brief comparison of the 20th and 14th centuries, the medieval period blighted by Bubonic Plague and constant warfare, Eagleburger recalled more modern miseries and argued that European leaders who are soft on terrorism are repeating the error of their predecessors who failed to face down Hitler.

"We are told by some in the United States and many in Europe that if we respond violently we will only contribute to the cycle of violence . . . . That, I would submit, is the logic that led Chamberlain to Munich," he said.

One good-news chapter in the history of this century, the former diplomat said, is the cooperative economic and military activity among western democracies, including Japan, since World War II. A reinforcement of the western alliance is the best prescription for curbing terrorism, he said.

Senior class speaker Thomas M. Fitzpatrick, meanwhile, warned his contemporaries not to "place blind trust in technology or in our policymakers." He recited a list of mishaps that experts had said were impossible, including the recent nuclear power plant disaster in the Soviet Union.

"When we are in charge, when we are leading this country, we will not blindly accept business as usual," he said. "We will challenge what does not make sense to us."