High Quality Content by WIKIPEDIA articles! The Illinois Senate career of Barack Obama stretched from 1996 to 2004, when Barack Obama was elected to the United States Senate. Starting in 1993 and throughout his state senate career, Obama also taught constitutional law part-time at the University of Chicago Law School, as a Lecturer from 1992 to 1996 and as a Senior Lecturer from 1996-2004, when he was elected to the U.S. Senate.