liggio had an international influence. in 1958, he attended his first meeting of the mont pelerin society in the united states, held at princeton university. he became a member of the program committee for the society's 1994 meeting at cannes in 1992. in 1996, he became its treasurer until 2000 as well as a member of its program and planning committee for the 1998 society meeting in washington, d.c. and of its board of directors until 2006. he became the chairman of its program committee for the 2002 meeting in london, england. he was then vice-president of the mont pelerin society from 2000 to 2002 and its president from 2002 to 2004. he has been senior vice-president since 2004 and due to leave in 2006.