DEAR MISS MANNERS: I have become sadly aware that a person in my community was verbally, emotionally and physically abusive to both of his spouses, one of whom just separated from and divorced him. I got this information independently from each of the women involved and without their knowledge of the other's report.
I have had a warm but not close social relationship with him, including one or two dinners over the previous five years. But after this all became clear and undeniable, he approached me at a party and attempted to make conversation. I was only able to utter "hi" and turn away, and it was difficult to not share my thoughts with him about his behaviors.
Is this the right response? I will likely see him again in the future at similar events. I also wonder if I should inform the hosts of my certainty about his character. I am unclear on my ethical responsibilities in this matter.
GENTLE READER: Ostracism is a powerful tool for expressing disapproval of bad behavior, although it operates separately from the legal system, and, more specifically, from courts of law and prisons.
If you have evidence to give to the authorities, then it may be your duty to do so, but assuming that is not the case, miscreants who have not been judged, prosecuted and perhaps punished may still fall outside the pale of polite society. Avoiding this person yourself is entirely reasonable and, depending on what it is you learned from the ex-spouses, it may even be allowable for you to share information with potential hosts.
Miss Manners issues only one caution, which is that given the lack of a formal determination of the facts on your part, you must be sensitive to the possibility that not everything you have heard is true. A remarkable number of 19th-century novelists made their careers on stories about unjust ostracism, and in those novels, the people doing the ostracizing are not the heroes.