Consider a case in which David, a union member, has been fired from his job on a production line in a factory. He was terminated

Consider a case in which David, a union member, has been fired from his job on a production line in a factory. He was terminated after he mistakenly dropped a wrench into some machinery which caused the machinery to malfunction and for the production line to be shut down for a full hour, which cost the company approximately $250,000 in lost production. David has worked at this workplace for 20 years. He was given a warning letter ten years ago regarding a minor incident of insubordination, but otherwise his work record is good with no other discipline. The department manager indicates in David’s termination letter the following: ” ” David’s union grieves his termination as a violation of the collective agreement’s requirement that discipline and discharge must be for just cause. During the grievance procedure, the grievance remains unresolved with neither the union nor the employer shifting its position. After the third step grievance meeting, the union decides referring David’s grievance to arbitration. David disagrees with his union’s decision and asks the union to reconsider its decision. He asks the union to change its decision and to take his case to an arbitrator.  The union declines to do so. You are a labour lawyer and David has contacted you in order to seek your advice about how he can get his grievance heard by an arbitrator even if his union has declined to advance it to arbitration. There are a number of things that, if David could prove one or more of them, could mean that his union would have to reverse its decision and take his case to arbitration. are those possible things that David would have to prove?  Fully explain them.  And to what body or organization would David have to prove these possible things?