An American University trustee who had been openly critical of ousted president Benjamin Ladner resigned from the board yesterday, saying he could not support the effort underway to negotiate a severance deal with Ladner.

Paul M. Wolff's departure followed that of the chairman, Leslie E. Bains, who left the board just days ago criticizing Ladner's "imperial lifestyle" and his supporters on the board.

"This is highly unusual," said Sheldon E. Steinbach, general counsel of the American Council on Education, "two trustees resigning in very public fashion, taking potshots at fellow trustees." It's unheard-of, he said, at a private university.

The resignations threw into stark relief the continuing bitterness on the board, which voted Monday to oust Ladner after an audit of his personal and travel expenses. The board concluded that he should reimburse the university $125,000 and add $398,000 to his taxable income for three years but did not agree on the terms of his departure.

Many on campus saw Bains and Wolff as two of their strongest advocates for change at AU. The board now has 22 voting members, down from 25 a few months ago, when Ladner also was a trustee. Although the board voted Ladner out, he still has strong supporters on the panel.

"My call for no severance is not vindictive, but necessary to show how serious we take his misdeeds, his damage to AU," Wolff says in his letter to trustees, obtained by The Washington Post from someone other than Wolff. "We must remember the cost already of Ben's excessive behavior."

Faculty and student leaders have urged the board not to give Ladner a "golden parachute" when he leaves.

The loss of Wolff and Bains could potentially affect his severance, according to other sources who asked not to be identified because of the sensitivity of the negotiations. Sources familiar with why Bains and Wolff resigned said both felt they no longer could be effective because of a lack of support.

Three trustees, perceived as representing a range of opinions on the board, were tapped to negotiate a departure package with Ladner. They are, the sources said, investment banker Gary D. Cohn, businessman Jack C. Cassell and Bishop John R. Schol of the Baltimore-Washington Conference of the United Methodist Church.

Ladner did not return a phone call yesterday, nor did his attorneys.

Wolff's letter also scathingly attacks trustees who supported the longtime president. He says some trustees want to return to the old culture of "secret agreements, concealed activities, and dereliction of duty."

There was considerable discussion during Monday's meeting of who was leading the board, with debate over when Bains's resignation took effect. Trustee David M. Carmen introduced a resolution at the Monday meeting to name Gary M. Abramson chairman, according to sources, but Thomas A. Gottschalk, who was chairing the meeting, ruled the resolution out of order.

Carmen, who said he could speak publicly only on issues that did not involve confidential board proceedings, said he has no idea who is running the board at the moment.

Carmen and Abramson are members of a group of 13 trustees who joined together in recent weeks, calling themselves the Ad Hoc Committee, hiring their own attorney and criticizing Bains and the other board leaders who voted to suspend Ladner in August.

Neither Bains nor Abramson returned phone calls.

Student leaders said they were worried about the resignations.

"I think the students have lost a very powerful advocate," said Peter Brusoe of the Graduate Leadership Council, who hopes to add student and faculty representatives to the board. "There was this chance all of a sudden to change the political culture of American University. I think that window still exists -- the problem is we're losing time to get those things taken care of and losing a lot of pro-reform allies." He said he trusted that Wolff was making the right decision and thought his departure might make the board coalesce.

Trustee George J. Collins said, "The university could use him going forward, in particular right now on the negotiations for Dr. Ladner's departure."

Carmen said that Wolff's departure was unfortunate but that his resignation letter had misstatements and would not help the university to heal.

Carmen did not say what the misstatements were.

Steinbach said it would be difficult to find a candidate to replace Ladner with the board in such disarray.

"This is like two warring spouses playing out on the front page of the paper with high-priced hired guns, rather than seeking an amicable resolution to their differences."