A decision like firing this employee is not made at high levels of management. Merely involving senior management in the issue is already an escalation. If the

A decision like firing this employee is not made at high levels of management. Merely involving senior management in the issue is already an escalation. If the union rep has a solid relationship with management, this conversation can be a simple "hey can you take a look at this". Management trusts that the union rep wouldn't approach them with frivolous complaints and looks into it, maybe reinstates the employee. If that trust relationship doesn't exist, then the rep would have to apply pressure somehow, which engenders bad will. Part of the job is knowing which fights are worth fighting, when they're worth fighting, and what sort of tools you're willing to use.