Legally actionable harassment in the workplace is disfavorable treatment based on an employee's race, color, religion, gender, national origin, age (40 or older), disability, etc. Retaliation occurs when an employer punishes an employee for engaging in legally protected activity, such a reporting actionable harrassment. Unfortunately, in your case, your principal's unwelcomed conduct is not based on any of the above criteria; it is solely based on her wanting her own hires. Accordingly, unless her actions violate the terms of an employment contract or union agreement, they are legal and you have no cause of action.