The problem with the Dutch system, is that coalitions can always get around Geert, because he’s not going to get 50 percent of the seats. Probably the only way it would happen is if Geert is the senior partner.
On the basis of the June elections, they are able to ignore Geert. If they are unable to form a government and elections must be redone, then Geert would be the driver's seat. In a new election, the Christian Democrats would be in trouble, because the people would see them as unwilling to join any coalition. CD voters would then have to pick another party for their vote to be meaningful, either go Labor or go Geert.