But in the last year, the university has been dogged by a string of scandals brought to light by The Los Angeles Times. First came reports last summer that the former dean of the medical school had used drugs on campus and partied with prostitutes. Then, last fall, the man who had replaced him was forced to step down after the university admitted it had settled a sexual harassment case with one of his former researchers.

Mr. Nikias had promised a full investigation of the scandal involving the medical school dean by an independent law firm last year, but several faculty members and university staff said they had grown impatient and angered that the results have so far been kept under wraps. Then came the reports last week of the decades-long history of misconduct allegations against the gynecologist, Dr. George Tyndall, and the university’s failure to report them to state authorities, former patients or the public.

Dr. Tyndall has denied allegations of any misconduct.

“It’s a clear pattern of something terrible happens and it’s allowed to go on for a long time, then there’s secret settlement and no taking care of victims, no public accounting,” said Ariela Gross, a professor of law and history who has been at U.S.C. for more than 20 years. Professor Gross began circulating a draft of the petition Sunday to tenured professors she knew and stopped when she had 200 signatories less than 48 hours later. “We know all that we need to know to know that we need new leadership. I’ve hardly been a consistent critic of our administration, but this is beyond the pale,” she said.

The faculty petition included many of the university’s most celebrated professors from more than a dozen schools, as well as former administrators. Still, it was unclear how much of an impact it would have. (U.S.C. has about 1,200 tenured faculty members.) Just one hour after the faculty letter was released to the public, the chairman of the board of trustees sent his own letter to students, staff and alumni affirming his “full support” of Mr. Nikias.

“The executive committee of the board has full confidence in President Nikias’ leadership, ethics, and values and is certain that he will successfully guide our community forward,” wrote John Mork, who is an energy executive in Colorado. The letter added, “We have zero tolerance for this conduct and will ensure that people are held accountable for actions that threaten the university student body.”