Stanfield Professor of International Peace Robert O. Keohane will leave the government department to assume a professorship at Duke University beginning July 1, Duke announced yesterday.

"The overwhelming reasons are personal. I want to be...with my wife," Keohane said yesterday. "I've been very happy for 11 years at Harvard."

The departing professor, an expert on international environmental policy, has been married to Nannerl O. Keohane, the current president of Duke, for 25 years.

She had been the president of Wellesley College from 1981 to 1993, when she left to assume her current post in North Carolina.

The Keohane family at the point moved to Durham, and since then Robert Keohane has been commuting to Cambridge for the work week.

Robert Keohane said in a statement that he is "looking forward to being home in North Carolina throughout the week, rather than just on the long weekends."

And his wife added that the move is "good news for our family."

As could be expected, the University was disappointed with the departure.

"Whenever one loses a major figure, the department mourns," said Kenneth A. Shepsle, chair of the government department, adding that Keohane was "one of the irreplaceable figures" in the department.

According to Shepsle, however, the departure will not significantly affect the caliber of the department. "We don't in any way feel that we are crumbling or falling apart," he said.

Keohane had initially rejected an offer from Duke in 1993, but this move did not come as a surprise to Shepsle.

"This was a shoe that was bound to drop," he said. "The issue was not whether, but when."

In fact, Robert Keohane spent last year in Durham as a Kenan Fellow at the National Humanities Center, during which time he wrote a book on the history of American foreign policy.

According to Joseph J. McCarthy, assistant dean for academic planning, the number of tenured professors who voluntarily leave is very low. An average of three tenured professors out of the 419 in the Faculty of Arts and Sciences resign each year.

The Keohanes have had to deal with an issue that is becoming "critical in all universities," he said.

New Obstacles

McCarthy said that a major new obstacle to recruiting has been created in that many spouses can not easily uproot themselves from their careers.

McCarthy also said it is "a nice compliment to Harvard that [Keohane] lingered" as long as he did.

Robert Keohane received his Ph.D. from the University in 1966, returned as a full professor of government in 1985 and served as the chair of the department from 1988 to 1992.

He specializes in studying the influence of international institutions on environmental policy and on other aspects of international relations.

When he arrives in Durham, he will become the James B. Duke Professor of Political Science, and hold a joint appointment in the Nicholas School of the Environment