When Cardinal Richelieu died in 1642, Pope Urban VIII pronounced: ‘If there is a God, Cardinal Richelieu will have much to answer for. If there is not… well, he has had a successful life.’ The red eminence, architect of the Peace of Westphalia, lived for 57 years. Henry Kissinger, by contrast, born Heinz Alfred Kissinger, is aiming to double that. On 27 May he will reach the milestone of 100. To paraphrase Urban, will he have something to answer for? History will tell us; for now, the examination has been postponed.

Born in Furth, Germany, Kissinger and his family, who were of Jewish origin, fled the Nazi regime and settled in the United States in 1938. There he began his academic career, eventually becoming a professor at Harvard University. Early in 1943 he was called up to serve in the US Army in the European theatre. His superior, Fritz Kraemer, impressed by the young man, recommended him for the military intelligence unit. That was how Kissinger came to join the Counter Intelligence Corps. Back in America, he graduated in political science from Harvard in 1950, distinguishing himself with his undergraduate thesis, The Meaning of History: Reflections on Spengler, Toynbee, and Kant, and obtained his doctorate in 1954. In 1952 he began working as a consultant to the director of the Psychological Strategy Board and launching the journal Confluence; a few years later we find him at the Council on Foreign Relations, and between 1956 and 1958 he was director of the Special Studies Project, sponsored by the Rockefeller Brothers Fund. Nuclear Weapons and Foreign Policy (1957) was the book that brought him to prominence in nuclear doctrine: in opposition to the policy of massive nuclear retaliation against a Soviet attack, he proposed a model of ‘flexible response’, combining tactical nuclear weapons and conventional forces. His acquired reputation as an expert political scientist enabled him to become an adviser to New York Governor and presidential aspirant Nelson Rockefeller.

In Kissinger, the combination of the scholar and the careful cultivator of relationships found its way into some of the most influential circles of American society. An adviser's expertise is not enough; to change things, it must be accompanied by influence over the Prince. Henry Kissinger, then, embodies the ‘philosopher king’, one of the rare cases of great scholars and academics who have managed to put their theoretical endeavours into practice. Kissinger was, indeed, National Security Adviser from 1969 to 1973 and Secretary of State from 1973 to 1977, during the Nixon and Ford presidencies.

The period from which his strategic thinking can be distilled coincides with the Nixon administration, at a time of crisis in US foreign policy. First came the decision not to end involvement in Vietnam, avoiding the greater risk of an abrupt withdrawal, which it was feared would lead to the immediate collapse of South Vietnam, damaging America's position in Asia and beyond. Here the ethical dilemma of great nations already emerges: a choice between two options one would prefer to avoid, while knowing that refusing to decide is impossible. This is the inevitability of tragedy in human history and in the life of the statesman. The diplomatic rapprochement with communist China, from which the United States had been estranged since 1949, following the end of the civil war and Chiang Kai-shek's flight to Taiwan, serves as an example of Kissinger's strategic thinking. With Kissinger's support, President Nixon made a pivotal trip to China in February 1972: the first-ever visit to the country by an American president. Kissinger supported the rapprochement between the two countries in order to make common cause against the Soviet Union. China was not an ally, but a lesser evil. It is difficult to deny the impact this choice has had on the contemporary world.

Vietnam, China, the USSR: testing grounds for Kissinger's thinking. What is that thinking? First, a premise: Hitler's rise left an indelible mark on the Jewish intellectuals who fled Germany. These men and women, Leo Strauss, Hannah Arendt, Hans Morgenthau and Kissinger himself, sought in various ways to bring the gravitas of old Europe alongside the naivety of the young American nation. In this sense, Kissinger can be seen as the European Chiron to the Achilles of American foreign policy, through a doctrinal approach rooted in classical realism.

A corollary of the aforementioned ‘tragic nature’ of relations between powers is Kissinger's declinist perspective on US power, borrowed from Spengler. Not in 2023, but in the 1970s. Hence the idea of splitting the communist front through triangular diplomacy, in the face of a Russia thought to have achieved ‘strategic parity’. The United States must think strategically, lacking the supremacy needed to cope with its imperial overstretch.

Concepts such as national interest, balance of power and rationality are the pillars of relations between nation-states immersed in an anarchic environment, preventing them from descending into chaos. Kissinger's approach to diplomacy assumes that the international order is ‘legitimate’, meaning accepted by the principal states. In the face of historical tragedy, moral principles must be applied with care, lest ideological positions devastate the established order. In relations between states, order is a precondition for effective diplomacy.

Categorical positions on ‘right’ and ‘wrong’ can be as dangerous as the crudest cynicism. The art of strategy and diplomacy lies in nuance, in shades of grey. In coming to terms with the world as it is, not as one would like it to be. Hope is not a strategy.

Of course, Kissinger's record is not beyond criticism. His involvement in the Vietnam War, including the negotiation of the Paris Peace Accords and the bombing of Cambodia, has been condemned by many authoritative voices, as has his management of political balances in South America. It falls to the reader to form an opinion, remembering that we can learn from both positive and negative examples: looking at the merits of one to follow its example, and the faults of the other to avoid them. If Kissinger was a flawed strategist, was the flaw in the theory or in its execution? And regardless of success, was he amoral?

In any event, Kissinger's contribution to contemporary and future diplomacy emerges from his intellectual legacy, which emphasises the importance of a systemic approach to global challenges, the so-called grand strategy: integrating a nation's different levers of power, military, diplomatic, political, economic and so forth, to achieve what it perceives as its national interests. This legacy is made available through his extensive literary output, a source of inspiration as well as insight for broad audiences at every latitude. His two latest books, The Age of AI and Leadership: Six Studies in World Strategy, bear witness to this.

We cannot know how Henry Kissinger will be remembered a hundred years from now. What is certain is that these first hundred have been enough to propel him into the pantheon of history's great statesmen. All that remains is to wish Henry Kissinger a happy hundredth birthday, in the hope that he celebrates it with the quality that most distinguishes him: balance, hopefully among old friends rather than among powers, at least until his next assignment.