Under what conditions should you decline an invitation to review a tenure file?

At Leiter Reports there have been two discussions that touch on this (HERE and HERE).  Reading and participating in these led me to wonder about the following question.

Under what conditions should one decline to review a tenure case?

Obviously if you are too busy to do a good job. And I think obviously if you think that your animus against the person or their work would hinder objectivity. But things are more complicated than this.

The problem is, objectivity hindering bias is hard to detect, both because heuristic biases are much harder to detect and correct in oneself than one usually thinks (e.g. Kahneman/Tversky) and because there are all sorts of relevant sorites series. Just consider the following kinds of circumstances:

1. I have an overwhelmingly negative view of some philospoher (let's randomly pick the appelation "Schmerida") that places me at the far end of certain 1980s culture wars involving him. I am asked to review the case of a self-described disciple of Schmerida who engages heavily in the kind of "performative" writing that drives me nuts (e.g. chiasmus, Nietzschean distance/loftiness, puns, and weird uses of parenthesis).
2. A substantive conclusion of my own published work is that view X is unustainable. The candidate both ignores my work and continues to presuppose (without argumentation) X in her substantive work.
3. If the candidate's main conclusions are correct, then a major presupposition of my work is undercut. To the extent that this candidate's work gains traction, my own disappears.
4. The candidate does not cite me, though s/he should!
5. The candidate is fundamentally confused about some key issue important to me.
6. The candidate is personally offensive.

I think that it should be clear that if one finds oneself reacting in any of the above ways to a candidate, then one should certainly not accept the invitation to take part in the tenure review of that candidate's work.

Why? The Kahneman/Tversky work shows pretty conclusively that you are one of the worst judges about whether or not your biases are making you irrational. As a result, all one can do is adopt policies that minimize possible harm that your own biases might cause. This requires trying to institutionalize epistemic humility in your own life.

Unfortunately, because we philosophy professors correct so many fallacies in our students' works, and because of the nature of the way research is caried out in analytic philosophy at least, we tend to be even worse about this thing. Contra Kant, we think we can recognize the good will as manifest in our own hearts. We think we are masters at objectively assessing pros and cons, as if writing a tenure review were in any way analogous to grading an introductory logic exam. So when we see anything that might flag an implicit negative bias, we should be very, very careful.

If you agree with me about the above, I think you will agree about a second point. In general, if you do not think there is a non-negligible chance you will recommend the candidate, then you should not agree to review the candidate. The main reason for this is that it is of the very nature of heuristic biases that you will not be an expert on whether you are objectively assessing the candidate or giving in to irrelevant biases such as the above.

There are other reasons for this besides dealing with heuristic bias. The most important of these has to do with the decision theory involved and the disproporitionate role that a negative reviews has, and this is (part of the reason) why there should be less concern about correcting for possible positive bias in this case. But, in any case, I think that the virtue of epistemic humility vis a vis the effects of one's own heuristic biases is sufficient.

Finally, let me clarify a few things. First, I am not saying one should be dishonest in the review. Nor am I saying that one should quit once one agrees to do it (one should not). So nobody is claiming that one should never write a negative review. Thus, even if everyone followed the policy (and I think most of us do) it will not render tenure a sham. Third, the main point of these reviews is not the thumbs up or down, but rather to patiently and charitably explain the candidate's work to colleagues and administrators who are not in the area and who may not even be philosophers. In my experience as someone who has chaired a few tenure committees, I think that most philosophy professors are admirable the way they do the hard work to follow this injunction.