Professor of International Law, Constitutional Law and Administrative Law at Fribourg University (1971-1977); Professor of Public International Law, Constitutional Law, Comparative Law and Administrative Law at Basel University (1977-1998), Dean of the Law Faculty, Rector, Basel University.
Judge at the Liechtenstein Supreme Court (1975-1988); Judge at the Administrative Tribunal of the Inter-American Development Bank (1989-1994); Judge at the European Court of Human Rights (1991-); President of the European Court of Human Rights (1998 -).
Chief coordinator and member of the Steering Committee of the Experts’ Commission for a complete revision of the Federal Constitution (1974-1978) - author of the Commission’s final report (1977). Member of the Advisory Board of the Federal Council for a complete revision of the Federal Constitution (1994-1996).
Expert for the Canadian Federal Government before the Supreme Court of Canada on the question of the legality of unilateral secession by Quebec (1997).
Numerous publications as the author of books, articles and as editor.
Languages: German, French, English