 From ABC News, I'm Sherry Preston. Two days after the assassination attempt on his life, former President Donald Trump has made his first appearance at the Republican National Convention in Milwaukee. He's also announced his running mate, Ohio Senator J.D. Vance. ABC's Perry Russom is there. A former Marine who served in Iraq, Vance rose to prominence after writing Hillbilly Elegy, a memoir about his life growing up in poverty.