I thought the user kalleman was just misinformed and slightly cranky, but his/her latest question (which I have locked and deleted) is fairly clearly trolling, and he/she also posted a troll answer to another question which has been deleted.
I want to suspend the user but realize I have no guidelines as to what constitutes a severe enough offense to suspend a user and how the lengths of suspensions should be related to the severity of the offense (as it were). Are there SE-wide guidelines written down somewhere I should be aware of? Should I just use my best judgment?