I know that there is a preselected candidate for a position to be filled at my department. What should I do?
One important consideration that you should take into account is whether there is an actual case of nepotism or not. Nepotism is if the preferred candidate is objectively inferior to at least one other candidate from all the information that is accessible to the selection committee. Or, in other words, if the head of the department is willingly hiring a worse candidate because they like them better, owe a favor to somebody, or have some other invalid reason to give one candidate preferential treatment.

The problem is that many "not really open" open positions aren't actually like that. In practice, what I often see as the main reason why a department or selection committee quickly zeroes in on a specific candidate is that they know much more about one candidate than about the others.

The most typical example is as such: There is an open search procedure, and a number of external candidates apply plus Alice, a candidate that has worked tightly with members of the department before, and which has been explicitly invited to apply. What you now see is a tremendous information asymmetry - the department knows little about the external candidates, but before they even open Alice's application folder they already have a great deal of information about Alice. They know what she can and can't do. Where other candidate's past successes are just a line in a CV to the committee, for Alice they know the full story, how she achieved them, what she has learned from them, and how this would help her be effective in her new position.

Recruitment is always a risky proposition, in academia just as in industry. We all have seen candidates that looked great on paper but turned out unsuitable for reasons that were impossible to glean from an application package. Faculty visits help, but how much can you really learn about a person in one or two days, especially in a somewhat artificial and often strongly rehearsed environment? In this situation, a risk-averse committee (and, realistically, this is basically every committee) has a strong incentive to go with Alice over a candidate that may have a slightly stronger CV, but also a much higher margin of error. As a consequence, a committee may prefer the "known candidate" Alice despite her weaker CV for completely rational reasons (which makes it different to nepotism). In essence, them doing so may be the optimal move for them given the information they have and how much they are willing to risk.




  What should I do?


Depending on how close you are to your boss, I would carefully try to find out why they prefer one candidate so much over the others (i.e., talk with them about it). It is completely possible that you may find that their reason is solid given the information that they have. Even if you disagree with their reasoning, understanding it may make the situation easier to accept for you. And if it turns out that there actually is a clear-cut case of nepotism (your boss knows the selected candidate is inferior, but decides to select them anyway), you have a much, much clearer argument for any potential whistleblowing.