There are several laws that are designed to protect employers in difficult situations. An example of that is the policy that prohibits an employer from firing an employee that reports wrongdoing, which is also known as whistle blowing.
Union employees may also be wrongfully terminated from a union contracted job, which typically is considered a breach of contract when the employee is fired. In these cases the Union itself may choose to represent the employee, providing both advisors as well as legal representatives for the case.