Is it permissible to disassociate with a close friend, if such a friend’s actions have become thoroughly corrupt? In my case, a warning was given, and after such a warning, that person’s actions only became worse, so I decided to disassociate with him. We pray daily that HASHEM distance us from an evil companion, and Pirkei Abot says not to associate with those who are wicked, yet there are those who are telling me that my actions cause divisions in Am Yisrael and are ’immature games’. If it matters, the person’s jokes included public statements and posts saying ’death to Israel’, and agreeing to lashon hara against a fellow Jew(not myself) while claiming these things to be jokes.This person is also highly learned and observant, so he knows that these actions are wrong. To be frank, when I cut off contact with this friend, that person took revenge against me, and thus my position was more strengthened. Who is right here, and what should I do?

Of course, there is no way of knowing "who is right?" when receiving a letter like yours. Even though you gave some information, the person in question may present a different case, and since I do not know you personally, I will not judge the issues of his behaviour. After that disclaimer, I will say this: If the friendship with this person is detrimental to your avodat Hashem, that is you feel this person influences you in a negative way, you are justified in distancing yourself, not as an act of judgement but as an act of self improvement. It is certainly possible that you are correct in your assessments. I would be careful not to judge to severely, unless you are sure that you have a true understanding of thei person and his motivations (something which is quite rare.)