CHICAGO (AFP) - John McCain is a man shaped by war. And he is a man who refuses to admit defeat. Not in politics, when the polls predict an end to his White House ambitions. Not in Iraq, even when the surge strategy appeared to be failing and the majority of Americans wanted to pull out. And not in the battlefield. Shot down during a bombing mission over Hanoi, the cocky fighter pilot spent five and a half years in a Vietnamese prison camp where he was tortured so badly he still cannot raise his arms high enough to comb his hair. While McCain was eventually broken into signing a false confession, he refused to break the code of honour by accepting an early release aimed at humiliating his father, who was commander of US forces in the area. And, unlike many Vietnam veterans who protested the war, McCain came home to defend it as an honourable and winnable war lost by weak-willed politicians. "I fell in love with my country when I was a prisoner in someone else's," McCain said when accepting the Republican party's nomination for president in September. If he wins the Tuesday's presidential election a McCain presidency will likely have a far more aggressive foreign policy than that promised by rival Barack Obama. He has spent much of his White House campaign warning that the "transcendent challenge of our time" is "radical extremism" and vowing to bring troops home from Iraq "in victory and honour, not in defeat."