By Sikhosonke Mayekiso

From the plethora of media commentary circulating globally, reaching even into the Global South, one can reasonably conclude that the second term of President Donald J. Trump’s administration constitutes a derogation from core principles of international law. Respect for sovereignty, the prohibition of non-intervention, and pacta sunt servanda; the duty to perform treaties in good faith have all been placed under significant strain. The consequences are both glaring and asymmetrically borne, inflicting acute harm on emerging economies such as South Africa. It is evident that this paradigm of aggressive unilateralism does not merely test the post-World War II international legal order; it actively undermines and erodes its foundations and hastens the shift toward a multipolar international system marked by fragmentation rather than cooperation.

The post-1945 international legal order was intentionally designed to forestall the recurrence of great-power rivalries and unrestrained aggression that had twice devastated the world in the first half of the twentieth century. The United Nations Charter, the Universal Declaration of Human Rights, the Bretton Woods institutions, and an extensive network of treaties and customary norms established a rules-based system in which sovereignty was upheld, the use of force was constrained, and collective decision-making afforded smaller states a measure of influence against the dominance of the powerful. Central to this architecture was the expectation of predictability: major powers would accept limitations on their freedom of action in return for legitimacy, stability, and the capacity to lead without constant recourse to coercion. This bargain, however fragile, relied fundamentally on the consistent adherence of the strongest participant – the United States to lend the system credibility and durability.

It is my central contention that the erosion of multilateralism under the current administration is neither incidental nor transient, but a deliberate and self-reinforcing strategy. By systematically marginalising institutions, treaties, and collective decision-making mechanisms, the administration hastens the very condition it professes to oppose: a world in which no single actor can depend on shared norms to exercise influence, and in which emerging economies are compelled to construct parallel arrangements to protect and further their interests. The United States is not strengthening its position; it is weakening the multilateral edifice that has historically magnified American authority while simultaneously affording smaller states with perhaps predictable access to global governance processes.

This deliberate strategy offers a nuanced perspective specifically one that reveals that this is no more than a calculated rejection of multilateralism commitments, setting off a chain of reaction of institutional decay. The Realist theory illuminates the underlying logic most persuasively: powerful states observe international law only to the extent that it aligns with their immediate interests. When multilateral obligations are perceived to constrain autonomy, they are set aside. The administration’s large-scale withdrawal from numerous international entities, including major United Nations-affiliated bodies concerned with climate, population, and human rights, exemplifies this approach. These withdrawals disregard the Vienna Convention on the Law of Treaties’ requirements of good faith and orderly termination, thus striking directly at pacta sunt servanda. Presented as the elimination of inefficient commitments, such actions in practice generate governance vacuums that rival powers promptly occupy, diminishing U.S. leadership and justifying further retreat. The result is a self-sustaining cycle as multilateral institutions lose credibility, participation wanes, and unilateralism becomes the default mode.

This dynamic is intensified when unilateral measures elicit adaptive responses from affected states, further fragmenting the system. The military operation that removed Venezuelan President Nicolás Maduro, conducted without Security Council authorisation, violated Article 2(4) of the UN Charter and normalised the use of force outside multilateral oversight. Such conduct invites reciprocal behaviour from adversaries and erodes erga omnes obligations against aggression, driving other states to seek protective alignments beyond established frameworks.

Historical precedents confirm that this pattern of erosion is both self-reinforcing and ultimately self-defeating. The 2003 U.S. invasion of Iraq, also undertaken without explicit Security Council authorisation, fractured alliances, generated regional instability, and accelerated multipolarity by creating power vacuums that other actors filled. Similarly, the Reagan-era trade unilateralism directed at Japan secured short-term concessions but undermined confidence in rules-based commerce and provoked retaliatory protectionism. While the post-World War I refusal to join the League of Nations isolated the United States and weakened the nascent system of collective security, contributing to the conditions that enabled subsequent global conflict.

The present course reproduces these historical dynamics. Short-term assertions of power yield long-term fragmentation. By eroding multilateralism, the administration compels emerging economies to hedge, diversify, and build parallel systems. South Africa’s deepening BRICS ties are one visible result.

A dominant state simply cannot indefinitely depend on rules it declines to observe. The erosion thus does not preserve American primacy; it dismantles the very architecture that has long sustained it.

Disclaimer: This post reflects my personal views only and is not legal advice. Consult a qualified professional for your specific legal and related queries.