The party has been in government for 11 years and hasn't waged the clearest of campaigns, so I do get it. As Jerome indicates, the Left is seen as either too extreme or as dirty because of implied ties to the former East German regime, and the Greens are positioning themselves as a bourgeouis party too much.

There's little motivation among SPD voters and little desire to go elsewhere, and apparently little organisational attention from the SPD to get people to vote.