The WASG (Wahlalternative Soziale Gerechtigkeit) was founded as a left alternative to the SPD by Union members and left social democrats.

I joined the PDS in 2004, way before the unification started. Legally, when WASG and PDS decided to run jointly in the Federal elections of 2005, WASG members joined the PDS and ran on her list. For this purpose, the PDS renamed itself in LINKSPARTEI (Left Party).

Both organizations still existing but have decided to merge by summer 2007. It is complicated, but I hope this helps.