 At this point in his career Laufenberg endorsed orthodox Marxism and supported Clara Zetkin in her ideological struggles with revisionists like Gerhard Hildebrand.He left the city in 1908 when he moved to Hamburg, leaving the Düsseldorf group without their leading intellectual.In Hamburg Laufenberg continued to work on the left of the SPD before becoming a member of the Independent Social Democratic Party of Germany splinter group.