[4] When Angelika Beer – a leading politician of the Green party at the time – was elected to be a member of the Bundestag, Germany's Federal Parliament, Nassauer served as a close adviser to her, especially with regard to her membership in the defense committee.
[5] Following the fall of the Berlin Wall in 1989, Nassauer organised a meeting between officers of the National People's Army from the Friedrich Engels Military Academy in Dresden and their West German counterparts from the Bundeswehr Command and Staff College in Hamburg.
[4][7] In the following year he and his co-director Siegfried Fischer, a former field officer of the People's Navy and military lecturer, edited the anthology Satansfaust, Das nukleare Erbe der Sowjetunion mit Beiträgen (The Fist of Satan: the Nuclear Legacy of the Soviet Union") with contribution by experts from both the Western world and the former Eastern Bloc.
[14] After the founding of the German section of the International Campaign to Ban Landmines in 1995 Nassauer supported it by co-authoring a study book about land mines made in Germany.
[16] Nassauer published his journalistic works regularly in a multitude of mass media outlets, amongst them the left-wing daily newspapers Die Tageszeitung (taz),[17] Neues Deutschland (ND) and Junge Welt, the weekly news magazine Der Spiegel,[18][19][20] and the bi-weekly Das Blättchen.
The fact that both his expertise and personality were widely appreciated was demonstrated by a multitude of obituaries not only from church and secular peace activist groups,[4][25][26][27][28][29][30][31][32][33][34][35][36][37][38] but also from leading journalists[39][40] and newspapers of record,[41][42][43][16] academia,[1] politicians of different parties and colours[44][5][45] as well as from military circles.