Doctor of Philosophy, Utrecht University, 1992.
Assistant professor Erasmus University, Rotterdam, Netherlands, 1986—1989, Utrecht University, Netherlands, 1989—1993. Senior legal adviser Ministry of Justice, The Hague, Netherlands, 1993—2000, since 2007. Professor constitutional and administrative law Maastricht University, Netherlands, since 2000.
Member board Dutch Section International Commission Jurists, Nederlands Juristen Comité voor de Mensenrechten, Leiden, Netherlands, 1989—1994, Organization Dutch Constitutional Law, Netherlands, since 2000. Substitute judge Centrale Raad van Beroep, Utrecht, 2002. Member board, division social science Netherlands Organization Science Research, The Hague, 2003—2006.
Director Montesquieu Institute, Center European Parliamentary History and Constitutional Development, Maastricht, since 2007. Teacher Dutch Academy of Legislation, The Hague, Netherlands, since 2001.