Trump is right. America is becoming polarized (see Antifa and the Alt-Right, Growing in Opposition to One Another in National Review – with antisemitism featured prominently on both sides (besides the BDS movement and its emphasis on “liberation politics”, the BLM movement has conflated antisemitism into its victimhood message, as has the toeva movement.
In fact, this is what characterized Germany at the end of the Weimer Republic period with frequent street battles between Nazis and Communists. On the other hand, I did hear that there is a tradition going back to Rav Chaim of Volozhin that Jews will never be persecuted as Jews in America. If America did not go fascist eighty years ago when all of the conditions were right it probably never will. Einstein, in fact, said this in response to Gödel’s assertion that the Constitution could be so interpreted.