When it comes to morality, diplomats are usually seen as cold and calculating. Machiavelli and Metternich are synonymous with the ruthless pursuit of interest verging on dishonesty. Sir Henry Wootton, Queen Elizabeth's Ambassador to Venice and Bohemia, described his profession as being made up of honest gentlemen sent abroad to lie for their countries. But good reasons exist for diplomacy's amoral tradition; paradoxically, this tradition embodies important moral values.
Many of us, despite our great respect for the US, react against phrases like "Axis of Evil" not because the countries listed do not present serious challenges, but because of the difficulties that follow from mixing foreign policy and morality. "Evil" is a religious term, not a foreign policy principle.
Foreign policy is about war and peace. If wars are fought on moral or religious grounds, no basis for restraint exists. After all, to call something evil is to invoke a moral duty to destroy it. No compromise, no modus vivendi, no peaceful co-existence is possible. Even containment is ruled out, for there is simply no room for negotiation and compromise. You cannot do business with the Great Satan.
Europe twice endured unrestrained wars. The Thirty Years War, fought over religion, laid waste to the Continent, killing one-third of Germany's population. Memory of the war's horrors led to a period of rationalism and restraint in international politics.