No matter how many people attack his foreign policy choices during the Cold War era, Henry A. Kissinger, the former Secretary of State under Presidents Nixon and Ford, shaped some of the most consequential moments of the last century. Thanks to his long connection with the academia of international relations and especially that of Harvard University, he had an opportunity to receive some questions about the conduct of global power politics in an event celebrating the 375th anniversary of Harvard. On one question asking him about how to become a statesman like him, he answered in a rather supposedly nuanced and shocking way—study history and philosophy.

This was not mere rhetoric. Simply by checking the titles of what Kissinger wrote at Harvard’s government department, we can notice two things easily: the homogeneity of perception of Kissinger as a student and then as a statesman, and the heterogeneity of his perceived day-to-day Machiavellian diplomacy and his inner conceptions inspired by great moralism and historicism. His bachelor thesis title was The Meaning of History: Reflections on Spengler, Toynbee, and Kant, and he wrote A World Restored: Metternich, Castlereagh, and the Problems of Peace, 1812-1822 as his doctoral dissertation.

The former dealt with the philosophy of history, and the latter discussed the nineteenth century’s European history of diplomacy. Why did Kissinger, who once seriously considered majoring in chemistry, spend a major part of his academic life in identifying the dynamics of historical philosophy and the decisions of old giants that only a few selected people could possibly figure out? This question of whether diplomats should understand not only the brief landscape of the confronting event and perceptions of those who are at stake but also their historical roots and philosophical implications must be answered as soon as possible.

Kissinger is not the only person who raises this kind of argument. Graham Allison and Niall Ferguson, who teach politics and history at Harvard respectively, suggested the introduction of the Council of Historical Advisers as part of the White House executive office. This notion that a strong background in history and philosophy is the ultimate passport to today’s diplomatic success mainly comes from a belief that history repeats itself endlessly. If so, historical facts and the philosophical lessons that organise the facts together can be a great textbook for diplomats and strategists. This metaphysical yet familiar assertion has its own merits.

In his book ‘What Is History?’, Edward H. Carr described the constant interdependence of the past and the present, society and individuals, and the unique and the general in the study of history. Even if some people do not accept his famous saying of “[history] is a continuous process of between the historian and his facts, an unending dialogue between the present and the past”, they should still recognise the importance of differentiating the partial events from the universal trend in the assessment of history. Some specific situations might not occur again, yet a broad direction of the past can appear in the future.

Graham Allison’s concept of the Thucydides Trap vivifies what history signifies in analysing geopolitical landscapes. Thucydides summarised the cause of the Peloponnesian War by saying “It was the rise of Athens and the fear that this inspired in Sparta that made war inevitable.” What Allison stressed was that a brief outline of this past experience–a contest between an established power and a rising power that became a war–might be somewhat inevitable in the arena of international power play. He found out that among the sixteen rivalries between two great powers since the sixteenth century, twelve cases ended in war.

This brings us back to the usefulness of statesmen’s learning of history. Decision makers in foreign policy should not ignore even a moderate possibility of the replication of the past, since their only mission is to set the best strategy by predicting the counterparts’ reactions and ultimately the future itself. Nevertheless, because of the relative inapplicability of small facts in determining the future, those who are responsible for leading the nation’s fate should be able to see a bigger picture. Understanding a series of wars and treaties is not enough; great strategists need great inspirations from philosophical ideas that frame the historical knowledge.

That every great power politics contains at least a certain degree of Spenglerian fatalism amplifies history’s significance. International relations is a giant zero-sum game; there is no way to increase every participant’s influence at the same time. When one nation stands out as a hegemonic power, other nations must lose some of their influence. Consequently, all nations have a burden from the past, defeatism for the present, and anxiety towards the future. This is the point where history plays a key role in politics; since there are less possible cases to consider, acquiring information about the patterns of the past becomes important.

A new trend of international politics, however, needs not just the data from historical research, but also a critical judgment of what is beneficial, what is possible, and what is just. Seeing the world through the lens of history and philosophy will be helpful, but that should not be the end of the story. Foreign policy officials of this century must lead their country beyond the known land of historical insights and explore between the Apollonian diplomacy of rational assessments and the Dionysian diplomacy of unpredictable decisions carefully as well as freely. Leaning too much towards any one side could be dangerous.

The dilemma between these two distinct attitudes towards the world has been clearest in the case of the United States where the stakes for the global order are highest. The Obama administration had failed to maintain a balance between moral values and uncertainty, whereas the Trump administration is already suffering from the clash between the liberal order and practical benefits. The Obama administration’s extremely Apollonian approach made the United States lose many potential leverages, but the Trump administration’s focus on the Dionysian strategy will be seen as too unstable even for the country’s traditional allies.

That President Trump’s foreign policy goal is not a return to the isolationism of the early twentieth century suggests new opportunities as well as challenges. The United States will continue to participate in global issues with a strict cost-benefit analysis based on transactional relationships. This may help address some of the issues in which different principles and egos are intertwined. A room for history and philosophy in the White House, however, seems to be smaller than ever. Policy choices misguided by the Dionysian desire without Apollonian insights will result in a breakdown of existing order, not its improvement.

The Trump administration has to be aware, especially when extreme populism reigned during the entire election process, that foreign policies of a political system based on democratically elected power are effective as well as dangerous. It will be much easier for the elected officials to garner public support than autocrats, and the scale of policy will therefore be greater, yet oftentimes the most popular choice among citizens may not be the best choice for the nation. Although ruling the country according to what has been promised to the voters is one of the essential principles of popular sovereignty, politics’ raison d’etre is to set the country on a right track.

While the scope of international politics should not be limited to empty conjectures as a result of contemplating too much and acting too little, it is still too risky to use the nation’s influence as a tool for expressing hate and reinforcing domestic grip without a right analysis of the present problems and their origins based on historical insights and philosophical ideas. As conflicts are endless in international relations, the inquiry of peace should always be with consistent and dedicated principles. To rephrase Immanuel Kant’s disputed quote, knowledge without action is a mere intellectual play, but action without knowledge is blind.