The (eastern) German Party of Democratic Socialism (PDS) survived for 15 years post-unification as a de facto regionalist party. During this time its attempt to expand its electoral base into western Germany largely failed and it found itself forced to act as a regionalist party in denial. Events in 2002?05 changed this position fundamentally. This contribution analyses, first, how the PDS survived as a regionalist party pre-2002. It then outlines how it nearly imploded between 2002 and 2005. Special attention is paid both to the PDS' eastern heritage as well as to the impact of multi-level politics on both political processes and outcomes. The nationalization of the PDS that has taken place since 2005 has come at the price of decreased levels of horizontal and vertical integration within the new Left Party, something that could have negative longer-term consequences for the party.