[S]exual harassment must be wrong either because a) proposing to pay for sex is wrong or b) radically changing a person’s job description from (e.g. from secretary to prostitute/maid/babysitter) is wrong.  That is, the employer’s threat must be to do something that is independently wrong. My intuition is that something like (b) makes sexual harassment wrong. In these extreme cases employees do have the authority to decline certain tasks that employers demand. In this case the employee may say ‘you led me to believe that the job did not require prostitution, so I have been deceived.’ Because it is wrong to deceive people, it is wrong to radically change a person’s job description, and so threatening to fire someone for refusing to comply with an impermissible demand is also impermissible.

My belief is that sexual harassment is wrong because it is an abuse of power. But libertarians have a hard time accepting the potential for abuse of power in the private realm: