Red lines have been flattened by Iran’s rapid progress toward a nuclear weapon and by Bashar Assad’s mockery, backed by Tehran, of US President Barack Obama’s warning that “proof of chemical weapons use would be a game changer.” By these revelations, two Israeli ex-intelligence chiefs Tuesday, April 23 underlined Israel-US differences on when to strike a nuclear Iran. DEBKAfile: They also aimed to stir the US into starting military action against Syria and moving on to strike Iran.