Good job.
The problem facing a possible Left government is, that a Labour Party commitment to making a Left government (with GroenLinks and SP) a priority, will likely cost them enough votes to make this combination not get a majority. That's always been the problem. Therefore, Bos does not want to come out and say that he wants to do this, despite pressure from GroenLinks and SP.
In the polls, the 3 parties on the Left don't even have the majority anymore. And since the economy is likely to improve a little, it is likely that the parties currently in government will improve on their standings in the polls too.
And, as you can read here http://www.peil.nl/?1782 , Labour has to choose. As CDA loathes Labour and vice versa, they will probably go for a coalition with the VVD, which makes a vote for Labour a vote for a left wing coalition, whether they like it or not (define or be defined). I'm not sure such grandstanding would help the CDA though.
And don't forget the Christian Union and D66 might join a left-wing coalition. Not very realistic, but not out of the question either.