Vocenoctum
First Post
I think it'd be pretty much impossible for the houses to remain totally neutral. If you don't have the money to get your army transported to the battle, but your enemy does, that's taking sides in the poor folk's eyes. 
Any time a House gives a seeming advantage to an enemy, it would be bad. Any simple failure of balancing the kingdoms against each other would result in conflict. Besides, the Houses are indeed located somewhere, and blaming your failings on such a simple reasoning isn't far.
I assume there's some alliance of the Houses, so attacking one would lead to all of the houses cutting off your kingdom, but that doesn't mean economic ruin if the country still has the resources.

Any time a House gives a seeming advantage to an enemy, it would be bad. Any simple failure of balancing the kingdoms against each other would result in conflict. Besides, the Houses are indeed located somewhere, and blaming your failings on such a simple reasoning isn't far.
I assume there's some alliance of the Houses, so attacking one would lead to all of the houses cutting off your kingdom, but that doesn't mean economic ruin if the country still has the resources.