Hartmann joined the SPD in 1983. He first became involved with the
Juso university group in Mainz and was chairman of the
Wackernheim and
Heidesheim am Rhein SPD local associations. From 1995 to 1999, he worked as a consultant for the support of subdivisions and commissions as well as advice on local and primary elections at the
Rhineland-Palatinate state association of the SPD. He then served as press spokesman for the Rhineland-Palatinate Ministry of the Interior from 1999 to 2002 under then Minister
Walter Zuber. He was chairman of the Mainz-Bingen SPD sub-district from 1999 to 2014 and was a member of the Rhineland-Palatinate SPD state executive committee from 2004 to 2014. From 1996 to 2005, he was chairman of the Social Democratic Community for Local Politics (SGK) in the Mainz-Bingen district. Hartmann first entered the
Bundestag as a directly elected member of parliament for the Mainz constituency in 2002. In the
2005 Bundestag election, he defended his direct mandate here with 40.9% of the first-past-the-post votes. In the
2009 federal election, Hartmann lost the direct mandate to
Ute Granold of the
CDU, but entered the
17th German Bundestag via the state list. In the
2013 federal election, he lost to CDU candidate
Ursula Groden-Kranich in the constituency with 34.9% of the first votes, but entered the Bundestag again via the state list. He was a member of the Interior Committee from October 2002 to July 2014, where he was the chairman of his parliamentary group from 2011. From December 2009 to July 2014, he was a member of the Parliamentary Oversight Panel for the Control of
intelligence agencies and from January to July 2014, he was a deputy member of the G-10 Commission, which controls the communications surveillance of intelligence services. Starting in January 2014, he was a deputy member of the Legal Affairs Committee, and since November 2014, a member of the Committee on the Affairs of the European Union. In July 2016, after a drug use controversy, Hartmann announced that he would not seek a mandate again in the
2017 Bundestag elections. From 2006 to November 2007, Hartmann was deputy chairman of the BND Investigative Committee and from November 2007 to 2009, he was the SPD parliamentary group's representative on this committee. From October 2011 to July 2014, he was domestic policy spokesman for the SPD parliamentary group. Since 2004, he has been a member of the district council of the Mainz-Bingen district and was last re-elected in 2019. In November 2017, Hartmann received the SPD's
Willy Brandt Medal.
Political positions During the 2013 federal election campaign, Hartmann spoke out against the legalization of
soft drugs. == Social offices ==