There was only one Henry Kissinger

The obituaries of Dr Henry Kissinger suggest that there were two Henry Kissingers: a brilliant diplomat who tried to end the Cold War and an unindicted war criminal implicated in the deaths of thousands of Vietnamese, Cambodians and East Timorese.

In fact, there was no contradiction between these two images. Kissinger was consistent: he was a Realist in International Relations, with an eye for the main chance.

Kissinger's approach takes us to the heart of the formal study of International Relations.

The formal academic study of International Relations began about a century ago, right after the trauma of World War I. University departments were created.

Two theoretical approaches in International Relations were created: Realism and Liberalism. In recent years there have been additional approaches, such as Peace Studies, with an emphasis on what unites people and states rather than what divides them, and Gender Studies, which has been a response to the domination of males in IR and International Law and the neglect of some issues such as the use of rape in war.

The author of the Realist/ Idealist distinction was the British historian Edward Hallett Carr (1892-1982), who is best known today for his book The Twenty Years' Crisis 1919-39.

Carr respected power over the illusions of liberal morality and expecting the best of other people and governments. He was critical of the Inter-War "peace through international law" movement, which was the belief that international law could provide a new route to the peaceful settlement of international disputes.

Carr received great deal of publicity because in those days there were so few professors of IR. He taught at the then University College of Wales Aberystwyth (Aberystwyth University remains a great university for IR).

He was no great supporter of Nazi Germany but (like many British Appeasers) he believed that the Germans had been treated unduly harshly by the Versailles Peace Treaty and that therefore Hitler's demands should be met.

During World War II he was working for The Times (London) writing pro-USSR editorials (though no great supporter of the USSR either). He continued to create controversy. He argued that the USSR was now the new force in politics and so had to be accommodated.

In other words, a person has to overlook their own personal preferences and morality, and simply go for the best deal available. Power and pragmatism - and not morality - should be the guiding principle. This is the works of Machiavelli applied to IR.

Kissinger has to be understood in this context. This provides the consistent thread throughout Kissinger's foreign policy. You don't have to "like" a foreign leader to do a deal with that person. Foreign policy is not for the squeamish or high-minded.