A former US Marine and Gulf War veteran has gone viral after calling Donald Trump a traitor deserving of execution by hanging, igniting fresh debate over the human cost of America's ongoing war in Iran. Kenneth O'Keefe, 56, a California-born activist and ex-serviceman, made the remarks following a visit to the ruins of a bombed primary school in Minab, southern Iran, where more than 150 civilians, the majority of them schoolchildren, were killed…