The answer is, of course, it depends. It depends so much on the specific situation that I don't even know where to start writing about how I would handle it, but here are a few questions I would ask myself, in no particular order.
From that list you can already guess that my first choice would not be firing them, but trying to solve the underlying issues that might be causing them to behave in a way that is disruptive for everybody else.
Yes but it's simple.
The company must have clear and precise rules and they must be managed by HR (if any) and published so everybody must know about it.
It is not as easy as to say "Rule 1: no douches!" because it's not clear what is a douche or how to not be a douche.
Second, we have an infractor (not a jerk, calling somebody a jerk is an easy way to be sued unless it is informally btw) and depending on their fault is the measure. If he or she must be fired, then it must be because he or she does something that is written down that involves being fired.
Third, a business is not a democracy (unless you are a shareholder). I have worked in A LOT of business and a lot of teams want to oust their chief. In some case, the team wants to chief out:
We agree on that, there should be clear and accessible policies defining what behaviours are unacceptable and people shouldn't be fired on the sole basis that someone else thinks they are a jerk.
However, I think it's reasonable to summarize a team's values with be considerate, don't be a jerk, I wouldn't expect Ilona to post a dense HR document defining what it means to be a jerk in their context.
It should the defined.
Team's value. What is that?.
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