In public, University President Lawrence H. Summers remained silent on the divestment issue during the five-month-long debate over Harvard’s holdings in the controversial oil stock PetroChina. But in private, Summers appears to have played a key role in encouraging the Harvard Corporation to sell its PetroChina stake in response to concerns about the oil firm’s links to Sudan.

“My instinct all along had been that this was quite a unique situation that potentially could warrant divestiture,” Summers said last night.

After news of Harvard’s holdings in PetroChina first sparked an uproar in October, Summers consulted with Michael Ignatieff, director of the Carr Center for Human Rights Policy, and Samantha Power, a Kennedy School lecturer who has helped to expose the ongoing genocide in Sudan’s western region of Darfur.

“I have long felt in my conversations with Professor Summers that he was looking to make the strongest possible case internally [for divestment],” Power said Monday evening.

Summers said that in December, he urged the Corporation Committee on Shareholder Responsibility (CCSR), which rules on ethical issues surrounding endowment holdings, to consider divesting from PetroChina.

Summers said last night that he was “pleased” by the CCSR’s decision to cut Harvard’s ties with PetroChina—the first time he has publicly expressed his personal views on divestment.

Summers said last month that the crisis in Darfur “is in many ways the major moral issue of our moment.” Yet he repeatedly referred questions on divestment to the CCSR.

But Power said that Summers’ public silence belied his active behind-the-scenes role. “I really think that this was an exercise of his leadership,” she said.

“A lot of people are going to say that this is something he is doing as damage control due to his personal difficulties,” Power said, referring to the uproar surrounding Summers’ remarks on women in science.

“But this train had left the station long before he became enmeshed in controversy here at Harvard,” Power said. “This was not damage control. If anyone suggests otherwise, they should come see me.”