 Sherrod Brown of Ohio is now the fourth Senate Democrat to urge Biden's exit from the race. Meantime, former President Donald Trump, who accepted the Republican nomination last night, says he has spoken with Ukraine's president and pledges to end the war. Also, Trump and his VP running mate, Senator J.D. Vance, will hold their first joint rally in Grand Rapids, Michigan, tomorrow. CBS's Charlie DeMar has the latest on the investigation into Saturday's assassination attempt on Trump in Pennsylvania. CBS News has learned that the shooter's parents attempted to contact him,