University President Lawrence H. Summers sits back for a lighter moment during an interview with the Crimson in June. In his resignation letter, Harper criticized Summers for past comments on women and minorities.

Conrad K. Harper’s resignation letter, released Monday, was as much an indictment of his fellow members on the Harvard Corporation as it was a condemnation of University President Lawrence H. Summers.

Harper had long been critical of Summers, those close to the two men say. But it was a dispute with James R. Houghton ’56, senior fellow of the Corporation, that prompted Harper to step down, according to Harper’s letter.

That revelation was likely to intensify scrutiny of the highly secretive Corporation, which has largely remained out of view even while it wields enormous power at the University. And Houghton, now the only member of the board who predates Summers’ tenure, could emerge as a central figure of campus discontent.

In the week since Harper’s resignation was announced, several faculty have already raised concerns with top Harvard administrators over Houghton’s leadership of the Corporation, according to one professor who has been briefed on these discussions. Those complaints are only likely to escalate come September.

Harvard’s seven-member governing board, which elects its own members and does not even release an agenda of its meetings, has no mechanism for accountability to the rest of the University. But Robert T. Ingram, president of the Association of Governing Boards of Universities and Colleges, defended the Corporation’s structure in an interview this week.

“It would give a lot of people more comfort if there were more than seven Corporation members and if there was less homogeneity in how they view the president,” Ingram said. But he added, “I just have a hard time imagining they would do anything but what’s best for the University.”

Faculty critics of the Corporation have focused their ire on Houghton, who controls the board, and Robert E. Rubin ’60, Summers’ closest friend among the trustees.

Although Harper spared no harsh words for Summers in his letter dated July 14, his real antagonist appears to have been Houghton, whom Harper described as unwilling to discuss Summers’ performance at the board’s annual retreat.

“He does not want time devoted at the retreat to the issue of salary,” Harper wrote of Houghton, adding, “I believe that plenary meetings are uniquely important for the wise administration of our affairs.”

In a statement released Monday, Houghton responded to Harper by spitting back his former colleague’s own words.

“In recent months there have been numerous occasions, in plenary sessions and otherwise, on which the members of the Corporation have shared with each other our perspectives on President Summers’s leadership,” he wrote.

Houghton, chairman and former chief executive officer of his family’s glassworks company, Corning Inc., is likely at the tail end of his service on the Corporation. At 69 years old, he is a year away from the board’s informal age limit, though the rule has been flouted before. Houghton’s 70th birthday is in April.

His departure would turn the Corporation’s top post over to Rubin, Summers’ long-time mentor and predecessor as secretary of the Treasury. Rubin was the board’s rookie member just three years ago, but in an unprecedented period of turnover on the board, he has rapidly ascended to an extraordinarily powerful position at the University.

For Summers, Rubin’s role on the Corporation is both a blessing and a curse. Rubin was, by all accounts, Summers’ greatest advocate during the presidential search and would surely be less inclined than most to fire his good friend. But Rubin’s presence has also reinforced the growing impression on campus of an acquiescent governing board packed with Summers’ own appointees.

Rubin angered many professors in January when The New York Times reported that he “was unaware of widespread faculty discontent with the management style” of Summers. Several professors made reference to that report in speeches at three contentious Faculty meetings this past semester.

Daniel S. Fisher, professor of physics and applied science, said at a Feb. 22 meeting that the Corporation “have shown shockingly little interest in what has actually been going on.”

Compared to its counterparts in the Ivy League, the Harvard Corporation is unusually small, secretive, and insular.

The Yale Corporation has 19 members, six of whom are elected by the school’s alumni. At Cornell, most trustees are limited to four-year terms. And every year at Princeton, students and young alumni elect a graduating senior to serve on its 40-member board.

Following years of precedent, Corporation members say little, if anything, publicly. As he has since January, Rubin did not respond to repeated requests for an interview. An assistant to Houghton said he was out of the country and unavailable for comment.

—Staff writer Zachary M. Seward can be reached at seward@fas.harvard.edu.