But the donor was furious and appalled at the school for introducing former President Donald Trump on the field at halftime of last November’s football game against Clemson. Dressed in a blue suit and striped tie, Trump smiled, clapped and waved to the crowd, which showered him with a mixture of cheers and jeers. “Give me a reason to believe in USC again,” the email to Athletics Director Ray Tanner said. “Give me a reason to consider establishing an endowment. Because at this moment I’m questioning the leadership of the athletic department and the university, and wondering if my money...