(Mark Humphrey | The Associated Press) In this Oct. 7, 2008, file photo, Democratic presidential candidate Sen. Barack Obama, D-Ill., left, and Republican presidential candidate Sen. John McCain, R-Ariz., greet each other at the start of a townhall-style presidential debate at Belmont University in Nashville, Tenn. Aide says senator, war hero and GOP presidential candidate McCain died Saturday, Aug. 25, 2018. He was 81.