 This is a special report from ABC News. Trump assassination attempt. I'm Chuck Sievertson. You know, the political record in this country has gotten very heated. It's time to cool it down. President Biden at the White House in a talk to the nation urged people to help end political violence. He's changed his Republican convention speech since yesterday's shooting, says former President Trump to the Washington Examiner. He says he'll now focus on national unity. On the investigation, ABC News contributor and retired NYPD chief of detectives Robert Boyce.