Career
He specializes in European constitutionalism, political theory and European affairs He received his doctorate in 1977 from the University of Frankfurt with a thesis "Praxisbezug und Theoriebildung" During the 2009-2010 academic year, he was the Theodor Heuss Professor at the New School for Social Research in New York City. He has authored a number of internationally-known books, including Adorno and Critical Theory (1999) and Solidarity: From Civic Friendship to a Global Legal Community (Massachusetts Institute of Technology Press, 2005), a book that is held in 419 libraries according to WorldCat.