A leading foreign policy scholar has warned that nuclear weapons are no longer merely instruments of war but have increasingly become drivers of international conflicts, diplomatic crises and military confrontations, posing an existential threat to humanity.
Professor Femi Otubanjo, Research Professor at the Nigerian Institute of International Affairs (NIIA), issued the warning on Tuesday while delivering a foreign policy lecture in Lagos titled, “Nuclear Weapons: From Instrumenta Belli to Causae Bellorum.”
According to him, while nuclear deterrence has helped prevent direct military confrontation among major powers since the end of World War II, disputes surrounding nuclear ambitions and capabilities are increasingly becoming triggers for geopolitical tensions, sanctions, proxy conflicts and preventive military actions.
“Nuclear weapons have moved from being mere instruments of war (instrumenta belli) to becoming causes of war (causae bellorum),” Otubanjo said.
The political scientist warned that the consequences of a nuclear conflict would extend far beyond the battlefield, potentially resulting in mass casualties, environmental devastation, economic collapse, political disorder, psychological trauma and the possible destruction of organised human civilisation.
Although discussions about nuclear weapons often appear distant to many Africans, he said no region of the world would be spared the consequences of a full-scale nuclear war.
“Their existence altered the distribution of power, encouraged doctrines of deterrence and generated unprecedented fears regarding the survival of humanity,” he said.
Tracing the evolution of nuclear weapons from the Manhattan Project and the atomic bombings of Hiroshima and Nagasaki to the Cold War arms race and contemporary geopolitical rivalries, Otubanjo noted that nuclear weapons have occupied a unique place in international politics since 1945 because of their unmatched destructive capacity and strategic influence.
He cited the decades-long tensions between the United States and Iran as a clear example of how nuclear issues have evolved into sources of international friction.
According to him, Iran’s nuclear programme has remained a major point of contention in relations with Washington since the 1979 Iranian Revolution, triggering sanctions, diplomatic standoffs, international negotiations and recurring security concerns.
“These developments demonstrate how nuclear issues have increasingly become causes of conflict rather than mere instruments of warfare,” he said.
Otubanjo explained that nuclear politics is largely shaped by three major theories: deterrence theory, balance of power theory and national interest theory.
He said deterrence theory gained prominence during the Cold War through concepts such as second-strike capability and Mutual Assured Destruction (MAD), under which states refrain from aggression because the costs of conflict outweigh any potential gains.
Meanwhile, the balance of power theory explains why nations seek military capabilities to prevent domination by rivals, while the national interest theory emphasises state survival, security and prosperity as the primary objectives of foreign policy.
The scholar described nuclear weapons as explosive devices that release enormous energy from atomic reactions, making them significantly more destructive than conventional explosives.
He identified two major categories of nuclear weapons: fission bombs, commonly known as atomic bombs, and fusion bombs, also known as hydrogen bombs.
According to him, modern nuclear warheads possess destructive capacities ranging from 100 to 800 kilotons, while the Soviet Union‘s Tsar Bomba remains the most powerful nuclear device ever tested at 50 megatons—about 3,300 times more powerful than the bomb dropped on Hiroshima.
Otubanjo attributed the absence of nuclear warfare since 1945 to three principal factors: deterrence, the hierarchy of national interests, and widespread recognition of the catastrophic consequences of nuclear conflict.
“Nuclear-armed states understand that a nuclear war would destroy all parties involved and therefore cannot be considered a rational policy option,” he said.
Quoting military strategist Carl von Clausewitz, he argued that war remains politics pursued by other means, adding that a war capable of destroying everything would serve no political objective.
He also noted that leaders generally place national survival above all other interests and have therefore exercised restraint in nuclear decision-making.
Warning against complacency, Otubanjo said even a limited nuclear exchange could kill millions of people, while a large-scale nuclear conflict could trigger global famine, societal collapse and the destruction of modern infrastructure.Quoting former Soviet leader Nikita Khrushchev, he concluded: “The survivors of a nuclear war, if any, would envy the dead.”