Mr. Monk's Other Brother - S7-E10
Revealing mistake: When Reese opens fire on Adrian, Jack and Natalie at his house, in a shot from Reese's perspective, the squibs from bullet hits on the ground appear to be below the barrel's trajectory. The bullets should be hitting the ground closer to his targets' feet.
Answer: The two men are trying to work out a secret deal between them without involving the union, which means the workers' interests aren't being represented and defeats the whole purpose of a union. The mayor would lose labor's support and Cusack's union troubles would just be starting.
Captain Defenestrator