I respectfully disagree :-)

This may appear to be the case if you only compare numbers with 2002 election results, but not if you compare it to poll numbers. As I argued here, the SPD actally increased its support (by 6%, and 8% above the minimum a few weeks later) after Schröder went for new elections and Lafontaine's resignation from the SPD kick-started the formation of the Left Party. This at the same time when the Left Party almost doubled its share over that of its predecessors' poll numbers, and the Greens ended up with the same 8% they polled at four months ago.

My explanation is: after the Left Party forced the SPD and Schröder to campaign with a leftist overtone rather than the same old same old, many voters returned.

_{*Lunatic*, n.
One whose delusions are out of fashion.}