None of them ever "do" thinking in any meaningful way, or have any capacity so to do. This is why they are in the mess they're in and why, when push comes to shove, we need to think very hard about giving them anything serious like weapons, in case they hurt themselves - or anybody else.
The biggest problem is that the same can be applied to many politicians, especially once they become part of the Government. They want little more than to go with the flow, do what some bigger authority says and feather their own nest. The MoD are incapable of pushing back against Ministers and Ministers are incapable of pushing back against Civil Servants. Yet the mechanism for doing so is right before their eyes - Parliament!