Mr. Monk vs. the Cobra - S3-E11
Continuity mistake: After Monk has been found in the coffin, Natalie and the captain comment on his smiling and the camera shows the candle has melted down all over Monk's hand. Then when the camera comes in closer, the candle is whole again and monk's expression has changed a little from the previous shot.
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