Clement was a member of the State Parliament of North Rhine-Westphalia from 1 October 1993 to 6 November 2002. Between 1994 and 2001, he was also was on the SPD State Executive in North Rhine-Westphalia (NRW), and was the deputy leader of the executive from 1996. He became a member of the SPD federal executive board in 1995, and served until his exit from the party in 2008.
