US President Donald Trump was interrupted by hecklers while campaigning in South Carolina for political newcomer Darline Graham in the race for her late brother’s Senate seat. One heckler wore a black shirt with a provocative message, while another protester approached the stage and shouted at Trump. Trump was backing Graham ahead of the Republican primary runoff after she faced criticism for struggling with a foreign policy question during a debate. The contest could test Trump’s political influence ahead of the November midterm elections.