The Horizontal Nature of German Politics

So Germany faces a problem. During the last election neither of the two main parties were able to gain a majority, not even with the help of their traditional allies. So they settled for a grand coalition between the two main parties in order to form a government. Neither were particularly happy, but presumably it would last a maximum of four years.

Well, four years are nearly up, and currently, things aren't looking good. Both of the main parties are slumping in the polls, so making a coalition with just one of the minor parties, as the main parties would like to do, may prove impossible. The solution would be a three-way coalition, however the parties are being picky. Basically the chart of German parties looks like this:


Parties that are beside each other are willing to work together, but not with anyone else. So for example, the CDU would like to work with the FDP, but no other party. FDP are willing to work with both the CDU and the SDP, but the CDU and the SDP don't want to work together. This leaves only four possible combinations for a coalition all members are happy with. Unfortunately, current polling doesn't favor any of them. Combined, this is their share of the votes:


Seems the only combination that might work is the CDU with the FDP, but if they don't capture a majority, there's going to be trouble.