At the moment, the SPD contesting the CDU/CSU's status looks more like a theoretical experiment designed to put pressure on Merkel. But maybe the Bundesverfassungsgericht will have to decide again (for the uptenth time this year... This election is really turning into a law class).

But still, despite the DSU-story, Schröder can't get around the fact that CDU and CSU are not competing.

However, the two-parties-argument is nothing but a formal legitimation for Schröder to do what he will do anyway: Trying to build a coalition.