One of the most significant ruptures in the global system occurred when the U.S. dropped atomic bombs on Hiroshima and Nagasaki during World War II. Since the middle of the 20th century, nuclear weapons have been one of the most important factors in international relations and the most important part of global security. A series of bilateral and multilateral agreements that have lasted for decades has made it possible to keep strategic stability, stop direct military conflict between great powers, and stop the spread of weapons of mass destruction. In this context, it can be said that conventional wars have geographical limits, but nuclear wars do not. So, the deterrence system that nuclear weapons create is naturally global in nature.

At this moment, a crucial and recent development indicates that the global system is transitioning into a phase in which the two principal nuclear powers are operating with significantly fewer constraints. The end of the New START Treaty, which limited strategic nuclear weapons between the U.S. and Russia, is not just the end of a legal agreement between two countries. It means that the nuclear stability structure that was built after the Cold War is slowly falling apart.

As the treaties expire

Nuclear weapons derive their destructive power from the immense energy released through the splitting (fission) or fusion of atomic nuclei. The most widely recognized expression of this principle is Einstein’s E = mc² equation. This formulation demonstrates that the relationship between matter and energy allows an extraordinarily small amount of mass to be converted into an unimaginably large destructive force. In essence, this is not merely a physical equation; it represents the foundational logic of modern strategic power, the mathematical expression of both ultimate deterrence and potential annihilation.

The U.S.' total control over nuclear weapons ended when the Soviet Union acquired them during the Cold War. In this light, one could say that the U.S. and the Soviet Union started to limit their nuclear weapons in the 1970s. At the beginning of the Cold War, the two superpowers started an uncontrolled race to build more nuclear weapons. But when the Cuban Missile Crisis in 1962 almost started a nuclear war, both sides knew they had to deal with the risks of nuclear weapons. The Strategic Arms Limitation Talks (SALT), which started in 1969, were a result of this awareness.

The Intermediate-Range Nuclear Forces (INF) Treaty came next. U.S. President Ronald Reagan and Russian President Mikhail Gorbachev signed it in 1987. So, the international system made ways for major players to limit themselves by balancing each other out. The INF Treaty came to an end when the U.S. withdrew from the agreement in 2019. This treaty was important in history because it was the first international agreement to get rid of a whole class of nuclear weapons. In real life, it led to the destruction of about 2,692 missiles, which is one of the most concrete examples of the two superpowers actually reducing their nuclear arsenals.

The end of the USSR in 1991 did not stop nuclear weapons from being made around the world, nor did it change the way nuclear competition works. At best, it only made things take longer. In this case, the START I Treaty, which was signed in 1991, limited the number of deployed strategic warheads to 6,000 and cut nuclear arsenals by as much as 80%.

The New START Treaty, which U.S President Barack Obama and Russian President Dmitry Medvedev signed in Prague in 2010, was the most recent and most advanced step in the long history of nuclear arms control.

The real break came on Feb. 24, 2022, when Russia invaded Ukraine. After that, the nuclear arms control regime began to unravel, and it has become very difficult to repair. The Biden administration extended the New START Treaty for a final five years in 2021, making it valid until Feb. 5, 2026. However, the treaty has now expired.

This change is highly significant because, for the first time since the early 1970s, there is no longer a legally binding agreement between the U.S. and Russia, the two largest nuclear powers, limiting their strategic nuclear forces.

On the other hand, we need to ask if these arrangements were good enough in the first place. The U.S. and Russia are not the only countries that use nuclear power. Instead, there are many nuclear powers in the world today, such as China, the U.K., France, India, Pakistan and North Korea.

Structural disintegration

To comprehend the current situation, the process must be viewed not only as the cessation of an arms control agreement but as the structural disintegration of the global strategic order. The changes happening today suggest a change that goes deeper than just a rise in the number of weapons: the weakening of the nuclear order's normative framework. This phenomenon is already evident in the context of U.S.-Iran tensions within the NPT framework and in Israel's policies throughout the Middle East.

There were very strict rules during the Cold War that controlled nuclear competition. Washington and Moscow saw each other as threats to their very existence, but they knew that if they did not control the nuclear domain, they would be more likely to destroy each other. The arms race and arms control developed concurrently for this reason. The system did not get rid of competition, but it made it easier to deal with. The core of strategic stability was not boundless authority, but controlled competition.

The expired New START Treaty indicated that both Russia and the U.S. could only have 1,550 deployed strategic warheads and 700 deployed strategic delivery systems, such as intercontinental ballistic missiles, submarine-launched ballistic missiles and strategic bombers. It went beyond just setting limits on numbers and made strategic transparency and predictability a part of the system by requiring inspections and sharing a lot of information.

In conclusion, the issue goes beyond physics or treaties: It reflects the erosion of the global nuclear order. The termination of agreements like New START signals not just the loss of legal limits, but the weakening of mutual trust, transparency and strategic stability that once underpinned global deterrence. Today, nuclear weapons exist within a more unpredictable and hybrid security environment, where the risk of unregulated competition has grown.