Frankfurter Professor of Law Emeritus Abram Chayes '43 died Sunday from complications of pancreatic cancer. He was 77.

Chayes, who served as a leading legal adviser to the Kennedy administration, taught at Harvard Law School (HLS) for more than four decades.

"Abram Chayes was one of the dominant figures in international law teaching and scholarship over the last third of a century," said HLS Dean Robert C. Clark.

After graduating magna cum laude from Harvard College in 1943, where he lived in Eliot House, Chayes served with the U.S. army in both the European and Pacific theaters of World War II.

After the war, Chayes enrolled in HLS, where he served as president of the Harvard Law Review and won the Fay Diploma, an award given to the student with the highest overall average in three years of study.

Soon after his graduation, Chayes served as a clerk to then Associate Supreme Court Justice Felix Frankfurter.

Chayes joined the HLS faculty as an assistant professor in 1955 and become a full professor in 1958.

He then worked as an adviser to the presidential campaign of John F. Kennedy '40. When Kennedy was elected, Chayes moved to Washington, where he was the legal adviser to the State Department. In that role, Chayes worked closely to develop the administration's response to the 1961 Berlin crisis, as well as the Cuban missile crisis.

"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.

"There were many who thought this was unpatriotic to say the least," she said. "It was quite the reverse. He loved this country."

Chayes continued working until right up until the end of his life.

In 1999, he was part of a committee of international legal experts that advised the government of Bosnia- Herzegovina on issues of corruption.

"He was simply a life force. They don't come like that often," Slaughter said.

Chayes is survived by his wife, Antonia Handler, five children and a sister.

A memorial service will be held at Harvard at a later date.