I hope you are asking this question from the case ‘The Arbitration Case Of Jesse Stansky’. In this particular case there was a system technician names Stansky who was terminated from his job because he had a argument with the co-worker and later hit him. Stansky not only violated the company rule but the handbook as well. In this case all the arguments have the importance while hearing of the case. In any organization the employee handbook and the company policy sets a work culture. All the unwelcoming activities like dishonesty, destruction of assets or policy, etc are restricted by these elements. It clearly state that any unwelcome activity will force the company to take disciplinary action.
As far as the labor agreement and mitigating factors are concern, these factors are also very important ot understand the incident happened in the organization. All these factors accumulately will help the arbitrator to take a decision about the employees fault and what disciplinary action has to be taken against him.