“He was optimistic at the time,” said Benedict Kingsbury, Mr. Franck’s successor as the Murry and Ida Becker law professor at N.Y.U. “He was a strong believer in the possibility of creating rule of law and democratic systems in these countries, but later became concerned about the dangers of nationalism and communal violence.”  Professor Franck later served as legal adviser to the governments of Kenya, Mauritius, the Solomon Islands, El Salvador and Chad.  From 1995 to 2007, he was counsel to Bosnia before the International Court of Justice in the case against Serbia concerning the July 1995 massacre of about 8,000 Bosnians in Srebrenica. “It resulted in a cautious judgment that Serbia was responsible for failing to prevent and punish those who committed genocide,” Professor Kingsbury said.  Professor Franck’s advocacy for international justice was rooted in his childhood experience as a refugee from Nazi Germany. Born in Berlin on July 14, 1931, he was the only child of Hugo and Ilse Franck. When he was 7, he and his family fled Germany just before Kristallnacht, the Nazi pogrom in November 1938. The family’s application for visas to the United States was denied, but after six months in Switzerland they obtained visas for Canada and emigrated to Vancouver.  Thomas Martin Franck received his bachelor’s degree in 1952 and his first law degree in 1953, both from the University of British Columbia. He earned a master’s of law degree in 1954 and a doctorate of juridical science in 1959, both from Harvard. In 1952 and 1953, he was a lieutenant in the Canadian Army. He began his academic career in 1954 as an assistant professor at the University of Nebraska.  Professor Franck was the author or co-author of 31 books on a wide range of international issues. His 1986 book, “Judging the World Court” (The Twentieth Century Fund), made the case for a substantial role for international courts. In “Resignation in Protest” (Viking, 1975), a book he co-wrote, he addressed the tension between the politician’s loyalty to a party and duty to the citizenry. His writings called for respect of international treaties like the Geneva Conventions and the Law of the Sea Treaty, which regulates peaceful and military use of the oceans.  “He argued for a robust United States engagement within the United Nations,” Professor Kingsbury said, “but also for vigorous reform of an institution weakened and ossified by the cold war.”  Professor Franck won two Guggenheim Fellowships, in 1973 and 1982; was president of the American Society of International Law from 1998 to 2000; and was editor in chief of the society’s journal from 1984 to 1993.  He is survived by his partner of many years, Martin Daly, whom he married in California last year.  A version of this article appears in print on , on Page A12 of the New York edition with the headline: Thomas Franck, 77, Dies; Advised Countries on Law. Order Reprints| Today's Paper|Subscribe
Mr. Franck was a prominent expert on international law who was particularly committed to promoting justice in developing countries.