He took a leading role in those organisations in promoting the anti-nuclear movement, advocating for multilateral disarmament by both NATO and the Warsaw Pact.
In May 1971 the West Berlin FDP elected him as their leader as he was the most prominent representative of the left-leaning wing of the party who was eligible for the role.
[9] Throughout his life, Lüder was a committed Humanist and member of the Humanistischer Verband Deutschlands and eventually became the head of their Berlin-Brandenburg chapter.
[10] He was also a member of the group Gegen Vergessen – Für Demokratie, the Karl Hamann trust and the German-Taiwanese Friendship Society.
[11] In 1980 he was awarded the Ordre national du Mérite by the French government and in 2012 he was given the honorary title of Stadtältester by the Berlin senate.