 ABC News, I'm Michelle Franzen. The investigation into the attempted assassination of Donald Trump continues in Pennsylvania. Police say they still don't have a motive. Donald Trump and Republicans moving forward with a message of unity at the RNC. ABC's Stephen Portnoy has more. Tonight's theme, making America safe once again, with a focus on illegal immigration, violent crime, and drug overdose deaths. Former Trump rival Nikki Haley is reported to be a primetime speaker.