Trump rally shooting the latest in history of political violence

Presidential historian Mark Updegrove spoke to ABC’s Whit Johnson about past shootings targeting political figures. Subscribe to ABC News on YouTube: ABC News Digital is your daily source of breaking national and world news, exclusive interviews and 24/7 live streaming coverage. Download the ABC News app for the latest headlines and alerts: Watch 24/7 coverage of breaking news and live events on ABC News Live: Watch full episodes of World News Tonight with David Muir here: Read ABC News reports online: ABC News is the home to the #1 evening newscast “World News Tonight” with David Muir, “Good Morning America,” “20/20,” “Nightline,” “This Week” with George Stephanopoulos, “ABC News Live Prime” with Linsey Davis, plus the