(CNN)Ted Cruz will launch his most forceful attack yet against Donald Trump in a TV ad that accuses Trump of buying political influence "in a pattern of sleaze stretching back decades." The 60-second spot, shared first with CNN, is part of a six-figure ad buy that will hit voters' TV screens across South Carolina starting as early as Thursday. It centers around Vera Coking, an elderly widow who faced the threat of losing her home in Atlantic City when the city tried to seize it through eminent domain — in order to allow Trump to build a casino parking lot....