Reply To: Is zelensky jewish?

One would need to check ancestry back to the the Russian Revolution (that would be his great-grandmother) and probably back to beginning of the “Haskalah” in the Russian Empire (another few generations earlier) which was in the mid-19th century. Unless someone is frum (meaning many hazakahs/presumption about yichus apply), or at least remembers when his family was frum, one should probably assume there is a safek, i.e. rescue him on Shabbos, don’t buy hametz from him after Pesach BUT don’t let him handle non-mevushal wine and don’t marry (with doing more research).