 The more we learn about Saturday's shooting of Donald Trump, the more we know it could have been stopped. The gunman on top of a rooftop who pulled the trigger, turns out there were cops inside that building. They just didn't know the shooter was up there. Secret Service Chief Kimberly Cheadle admits there were a lot of problems. The buck stops with me. I am the director of the Secret Service. It was unacceptable, and it's something that shouldn't happen again.