"It was, especially in retrospect, an extraordinarily exhilarating time to be in Washington," Chayes once wrote. "Much was possible and almost everything seemed fun. Whether this is truth or incurable utopianism, I'll leave to others."

After his stint in government, Chayes worked for an international law firm for a short time, before returning to HLS.

At HLS, Chayes was a popular and dynamic professor, whose books and articles on international law were widely read.

"He was one of the greatest teachers of the law school," said friend and colleague Anne-Marie Slaughter, Armstrong Professor of international, foreign and comparative law. "He could electrify a class and push them and leave them not only loving it and loving him, but completely enthused about any topic--even some very dry ones."

Throughout his teaching career, he remained active in shaping international law. He served as a foreign policy adviser to the presidential campaigns of Sen. Robert F. Kennedy '47, Sen. George McGovern and President Jimmy Carter.

Chayes also represented the government of Nicaragua in its World Court case against the United States' support of the contras in the 1980s.

Slaughter, who worked with Chayes on the Nicaragua case, said his decision to take on the U.S. government was controversial at the time.