End of the nuclear deterrence agreement between Russia and the US: what changes in global security and is there a threat to the world and Ukraine

On February 5, the New START Treaty, the last remaining agreement limiting strategic offensive nuclear weapons and providing for mutual control mechanisms, officially expires between the United States and Russia. Military analyst Ivan Stupak told UNN journalist what this means for Ukraine and whether the world will become more dangerous.

What is the "New START Treaty"

On Thursday, February 5, the New START Treaty, an agreement between the United States and Russia on large-scale nuclear arms control, signed in Prague in 2010 by US President Barack Obama and Russian President Dmitry Medvedev and entered into force in 2011, expires. The treaty was signed for 10 years, but in 2021, Vladimir Putin and Joe Biden extended it for five years.

Such an agreement obliged the US and Russia to reduce the number of their nuclear warheads to a maximum of 1,550 on each side, and the number of delivery systems, such as intercontinental ballistic missiles, submarine-launched missiles, and bombers, to 800 on each side. To control the agreement, an inspection was established to check both countries for compliance with the agreement.

Why did New START exist and what does its termination really mean for Ukraine and the world?

The New START Treaty was signed between the United States and Russia to limit the number of strategic nuclear warheads, carriers, and delivery systems. It also provided for mutual inspections, information exchange, and warnings about weapons movements to avoid accidental escalation or misinterpretation of the parties' actions, explains the military analyst.

This treaty did not arise from goodwill, but from cold calculation. Two nuclear powers understood that they had so many weapons that they could destroy the planet several times over. New START was needed not for disarmament, but so that the parties would not fear each other's every move and would not perceive exercises or missile movements as the beginning of a war.

As Ivan Stupak explains, at the peak of the Cold War, which fell in 1986, the total number of nuclear warheads in the world was estimated at approximately 70,000 units. This figure includes the arsenals of all nuclear states at that time, primarily the US (~23,000) and the USSR (~45,000), whose stocks accounted for the bulk of the global arsenal.

Today, global nuclear arsenals are significantly smaller. Thus, at the beginning of 2026, the total global stock of nuclear warheads was estimated at about 12,300 warheads, of which the US owns 5,177 and Russia 5,500 units. However, even current arsenals are more than enough for catastrophic consequences. That is why not the numbers, but the mechanisms of control and predictability played a key role.

"Inspections, data exchange, notifications of strategic system movements - all this reduced the risk of a fatal error. It's like when two people are sitting at a table with loaded pistols and warn in advance if they reach for a weapon, so that the other side doesn't get scared and shoot first," says Ivan Stupak.

At the same time, the expert emphasizes: in fact, the treaty has not been fully implemented for a long time. Due to the war and the breakdown of diplomatic contacts, inspections between the parties were stopped, and trust was lost.

"In essence, this treaty has long worked only on paper. Bilateral delegations did not visit each other, and Russia systematically demonstrated contempt for any international agreements. Therefore, its termination is rather a legal formalization of the reality that developed earlier," explains the military analyst.

A separate question: does the end of New START mean the beginning of a new nuclear arms race? According to the analyst, theoretically, the parties get more freedom of action, but practically this does not guarantee a massive build-up of arsenals.

The nuclear arms race is extremely expensive. The Soviet Union at one time could not withstand this burden and collapsed economically. For Russia today, a massive build-up of nuclear potential is a financially devastating scenario that can only accelerate its degradation.

The expert also draws attention to the state of the nuclear arsenals of the United States and Russia. According to him, even the maintenance and modernization of existing systems requires colossal resources, and the creation of new ones - even more.

"In the US, many intercontinental missile silos have remained since the Cold War. Their maintenance and modernization cost billions of dollars. This is not a button that can simply be pressed, it is decades of work and huge money," the analyst emphasizes.

As for Ukraine and Europe, Ivan Stupak says that he does not see a direct threat related specifically to the termination of the treaty, because the key deterrent, according to him, remains the strategy of mutually assured destruction.

"Nuclear powers still operate under the Strategy of Mutually Assured Destruction (MAD). This is a Cold War military doctrine according to which the use of nuclear weapons by two opposing sides (then the US and the USSR) would lead to the complete destruction of both, making a first strike meaningless. It is based on 'nuclear parity' and the inevitability of a retaliatory strike, which deterred superpowers from direct conflict. In simple words: if you strike, you will be struck back, even if there is no one left to give the order, the system will work automatically. This is what deters the use of nuclear weapons much more strongly than any treaty," the expert emphasizes.

In addition, geopolitical factors also influence the situation, in particular, China's position, which opposes Russia's use of nuclear weapons, including against Ukraine, is also a deterrent.

China has made it clear that the use of nuclear weapons is unacceptable. And Russia is too economically dependent on China to ignore this position. Therefore, the Kremlin's nuclear threats remain more of a tool of intimidation than a real intention.

In conclusion, the military analyst notes: the termination of New START does not radically change the balance of power in the world, and fears of immediate nuclear escalation are exaggerated.

Ukraine and Europe have already passed the peak of nuclear blackmail. We have overcome our fears. This treaty was an important element of security, but its end does not mean that the world will be on the brink of nuclear war tomorrow.