TROY -- Two top administrators are leaving their leadership posts at Rensselaer Polytechnic Institute.

The abrupt departure of Chief of Staff and Associate Vice President Laban Coblentz is reportedly due to his criticism of the administration of President Shirley Ann Jackson, according to multiple sources with knowledge of the situation. Provost Robert Palazzo is also leaving his post, though the school says he will return after a yearlong leave of absence.

The dismissals signal a possible growing dissension at the highest levels of RPI's governance. Jackson has had a long-running dispute with the faculty senate, which she dismissed in 2007, one year after it narrowly failed to pass a no-confidence vote in her leadership.

The school has expanded significantly under Jackson's decade-long tenure, adding buildings, programs and increasing its national reputation. That has come at a cost, however, as RPI now grapples with a debt load of $806 million and has drawn heavily on its endowment to achieve Jackson's goals in recent years.

In addition, the school's ranking on the influential U.S. News & World Report list has been dropping after years of climbing. It fell to 50 on the recent list of national universities, down from 42 just two years ago.

Coblentz's dismissal is particularly significant. He has known Jackson longer than almost anyone at Rensselaer since they worked together at the U.S. Nuclear Regulatory Commission. Coblentz was a senior adviser to Jackson from 1997 to 1999, when she was chairwoman of the NRC.

He was also a speechwriter and communications adviser to current Egyptian President Mohamed ElBaradei. He came to Rensselaer from Vienna, where he worked for the International Atomic Energy Agency. Coblentz declined comment on his departure. Palazzo did not return phone calls seeking comment.

William Walker, vice president for strategic communications, called Coblentz's situation a personnel matter and said the school would not issue a statement.

While Coblentz's departure was immediate, Palazzo will remain as provost through the remainder of the year, then will go on a year-long sabbatical before he returns to his duties as a biology professor.

In an email sent to staff, Jackson praised Palazzo and said students would benefit from his changing role.

"He will be relinquishing his administrative responsibilities so that he can return to the faculty and devote his full energy to teaching, research, and academic scholarship," she wrote. "As a tenured Professor of Biology, his value to Rensselaer will be felt most keenly by our students, whose education and research opportunities will be enriched by his teaching, research, and leadership abilities."

Reach Waldman at 454-5080 or swaldman@timesunion.com. Follow him at www.Twitter.com/518Schools.