I love the movie Michael Clayton for its insights into corporate pathology. But I think this scene below is also a perfect introduction into the process of helping one side in an impending conflict great real about their situation and come to see their interests and the way forward, against their magical thinking that they can get away with something.
I also think that something like this could be said by British Chancellor Philip Hammond over Brexit discussions in the British cabinet.
The key lines are:
"There's no play here. There's no angle. There's no champagne room. I'm not a miracle worker, I'm a janitor. The math on this is simple. The smaller the mess, the easier it is for me to clean up."