The behavior of U.S. President Donald Trump in foreign policy constitutes a genuine puzzle for many observers, political analysts, and academics worldwide. From sudden withdrawals from international agreements, to cycles of escalation followed by retreat, and from strained relations with allies before adversaries, U.S. foreign policy during his presidency appeared inconsistent and difficult to explain through traditional theories alone—those that link state behavior primarily to balances of power or national interests. This raises a fundamental question: can Trump’s foreign policy be better understood through the president’s own personality and individual traits?
To address this question, I draw on two important intellectual frameworks within the field of international relations. The first was developed by the American scholar and international relations theorist James Rosenau, who devoted significant effort to challenging one-dimensional explanations of states’ external behavior. The second comes from the contemporary British international relations theorist Barry Buzan. Both frameworks underscore the importance of the individual factor in foreign policy decision-making.
James Rosenau (1924–2011) was among the earliest scholars to challenge the dominant assumption that foreign policy is an inevitable product of international structure alone. In his seminal work Pre-Theories and Theories of Foreign Policy, Rosenau introduced a multi-level analytical model comprising four principal dimensions: the individual, the societal, the governmental, and the international systemic levels. He emphasized that understanding foreign policy cannot be confined to the international system alone, but must take into account the interaction among these different levels. What distinguished his approach most clearly was his emphasis on the decisive role of the individual variable—namely, the leader’s personality, psychological traits, and perception of reality—particularly in cases where leaders enjoy significant autonomy or where institutional constraints are weak.
Rosenau argued that individual-level variables become especially decisive during periods of crisis or when leaders possess unconventional personalities. He maintained that foreign policy is shaped not only by institutions and structures, but also by the leader’s cognitive framework and behavioral patterns. This perspective represented one of the earliest systematic efforts to incorporate political psychology into the analysis of foreign policy.
Applying this framework to Trump’s experience is particularly revealing. Trump was not a conventional politician, nor did he emerge from the diplomatic or military establishment. Instead, he brought with him a business-oriented mindset, a pronounced populist inclination, and a tendency toward abrupt decision-making—often communicated through social media—without adherence to established institutional channels. These individual traits, in Rosenau’s terms, help explain decisions that appear sudden or unpredictable when assessed through traditional analytical lenses.
Barry Buzan, a British national and Emeritus Professor at the London School of Economics and Political Science, is among the most influential contemporary international relations theorists and a central figure in the Copenhagen School of security studies. Throughout his scholarly career, Buzan has contributed to broadening the concept of security to encompass political, social, and cultural dimensions, while emphasizing that the modern international system cannot be understood through institutional structures alone.
In a recent post on his LinkedIn page, Buzan wrote a brief yet pointed reflection stating:
“Some of you may remember studying Rosenau’s Pre-Theories and Theories of Foreign Policy from the 1960s. He set out a range of explanatory variables, including individual, role, societal, governmental, and systemic variables. It is clear that we are living in a period in which individual variables play a major role, with Trump at the forefront. I propose coining a new term—‘megalomania’—to describe the current reality of U.S. policy, both domestically and internationally.”
By integrating Rosenau’s theoretical framework with Buzan’s observations, Trump’s foreign policy behavior can be interpreted with greater precision. The withdrawal from the Iran nuclear agreement, skepticism toward NATO, and tensions with traditional allies cannot be fully understood through balance-of-power logic or national interest calculations alone. Rather, these actions clearly reflect the president’s personal temperament and individual disposition, as well as the absence—or weakening—of traditional institutional oversight mechanisms that typically constrain leaders’ behavior.
In this context, Trump’s presidency emerges as a vivid illustration of the renewed centrality of the individual variable in international politics. It serves as an important call to reassess prevailing interpretations of U.S. foreign policy and to recognize that a strong and unconventional leader’s personality may become a decisive factor—at times more influential than institutionalized strategic planning.
This phenomenon conveys a stark and unequivocal message to political analysts and foreign policy commentators who now proliferate across global media and social media platforms: foreign policy is not always rational or coherent, as classical political theories often assume. Instead, it can be a direct reflection of a leader’s personality, particularly during periods of weakened institutional constraints. Herein lies the enduring value of the contributions of Rosenau and Buzan: the former provided the theoretical foundation for understanding the individual variable, while the latter demonstrated that this variable has become powerfully salient in contemporary political reality.
In my view, the experience of President Trump—despite its limited duration and scope—offers an important lesson: understanding contemporary international relations and global politics requires more than structural analysis alone. The leader’s personality and individual traits must be taken into account. This makes analytical openness, intellectual integration, non-bias, and freedom from ideological rigidity indispensable tools for journalists, analysts, and academics alike.
Author’s Note:
An earlier version of this article was originally published in Arabic in the Lebanese newspaper An-Nahar on Wednesday, January 28, 2026. The motivation for writing this opinion piece was a remark made by Professor Barry Buzan, Emeritus Professor of International Relations at the London School of Economics and Political Science, in a post on his personal LinkedIn account, in which he described the current phase of U.S. policy under President Donald Trump as a phase of “megalomania.”
