From what I can observe from this distance, Newark Mayor Cory Booker gets props from both Dems and Repubs...however, if he were to become a serious threat to Chris Christie, the Repubs would turn on him in a NY minute. As of now, the Repubs are happy a Dem is in charge of a historically unmanagable city with low scholastic scores/high drop-out rates - a city once home to the Pru Insurance Corp, but has not been able to attract good-paying jobs (imo, directly related to a poorly-educated population). The good earners of corps still in Newark flee the city at 5pm for the burbs and do not leave their money in city.
Newark, NJ is not unlike any other old city that was racked by riots and seemingly never fully recovered.