 And the convention opens. It will be riveting for the next four days here in Milwaukee. Good morning, I'm Cammie McCormick with the CBS World News Roundup. The assassination attempt on Donald Trump over the weekend rattled the nation and happened at a rally in Butler, Pennsylvania on Saturday. The shooter was killed by Secret Service snipers. CBS News correspondent Scott McFarlane was at the rally and reports it's left many questions about how it could have happened.