US-Russia nuclear deal expires today. What does it mean for the world?

The last nuclear arms control agreement between the US and Russia is set to expire on Thursday. So does the restraint on deployment of nuclear warheads, raising fears of an unbridled nuclear arms race between the two superpowers. What has triggered concerns is that both US President Donald Trump and Russian President Putin have been reluctant to extend the treaty amid tensions over the Ukraine war. It effectively spells a death knell for nearly three decades of arms control cooperation between the US and Russia that helped bring an end to the Cold War.

Now, why does this matter? The US and Russia possess 87% of the world's nuclear weapons. The Strategic Arms Reduction Treaty, known as 'New START', which was renewed in 2010, not only placed limits on the nuclear arsenals of the US and Russia, but also included compliance and verification mechanisms.

WHAT IS THE US-RUSSIA NUCLEAR TREATY?

Under it, both sides had to share information on the movement of strategic nuclear forces. On-site inspections of missiles at short notice were also part of the deal.

The 'New START', signed by former US President Barack Obama and Russia's Dimitri Medvedev in 2010, crucially gave Moscow a roughly equal footing with the US as a nuclear superpower. The treaty, which was extended for five more years in 2021 by Joe Biden, capped nuclear warheads for both sides at 1,550.

Its expiry has now raised the terrifying prospect of a world without nuclear limits. To put it simply, the US and Russia are now free to produce as many nuclear missiles as they want.

WHAT HAVE TRUMP AND PUTIN SAID?

And both leaders have shown no desire to renew the deal. Trump has sounded less concerned, telling the NYT last month, "If it expires, it expires". In fact, the US President has been a vocal critic of international limits and last year ordered the military to resume testing of nuclear weapons.

On the other hand, Russia has declared it was no longer bound by limits on nuclear warheads, after an offer to Trump to extend the treaty by a year went unheeded. However, Putin, in a call with China's Xi Jinping on Wednesday, said Russia would "act in a measured manner and responsibly", AP reported.

Russia's Medvedev, who signed the treaty with Obama in 2010, warned of the danger of allowing the deal to lapse. "This immediately means a catastrophe and a nuclear war will begin... it should still alarm everyone," Medvedev told reporters in Moscow.

A key stumbling block has been a demand by the US to include China in any future arms control treaty. The US has been wary of China ramping up its nuclear arsenal. It also raises concern for India, which shares border disputes with China even though there has been a thaw in ties.

However, China's nuclear warheads, believed to be around 600, is 12% less than the size of the US arsenal.

Meanwhile, Russia has sought the inclusion of France and the UK - Europe's nuclear powers - in any future deal.

HOW HAS THE WORLD REACTED?

The development has rattled the United Nations, which has urged the US and Russia to quickly renew the deal. UN Secretary General Antonio Guterres, in a statement, said the risk of a nuclear weapon being used was the highest in decades.

"For the first time in more than half a century, we face a world without any binding limits on nuclear arsenals of two superpowers," he said.

The Pope also stressed that both sides should do "everything possible" to avert a fresh nuclear arms race.

Now, you have understood the gravity of the matter. But the expiry of the US-Russia deal does not concern these nations only. It has implications for the world.

WILL IT START A NEW NUCLEAR ARMS RACE?

The immediate fallout could threaten the 1970 nuclear nonproliferation treaty (NPT), which is up for review later this year. In fact, the expiry of the US-Russia deal weakens the very foundation on which the NPT rests.

Under the NPT, countries without nuclear weapons have pledged not to acquire them. In return, the nuclear countries promised to reduce and eventually do away with their arsenals. Now, if the US and Russia again start ramping up their nuclear weapons, non-nuclear countries can well accuse them of breaking their side of the deal. It will only spur a global nuclear arms race.

In reality, both the US and Russia have already started modernising their nuclear forces. In fact, a new arms race is already underway.

Last year, Russia tested a nuclear-powered intercontinental super torpedo called Poseidon and Burevestnik, a nuclear-armed and powered cruise missile.

Against this backdrop, Trump has intensified plans to build a "Golden Dome" to protect North America from long-range weapons. In fact, he has pointed out that this threat from Russia is behind his Greenland takeover ambition.

The 2025 Netflix thriller 'A House of Dynamite' depicts a crisis in the US where an unidentified ballistic missile is launched towards it. While the thriller was based on a hypothetical situation, no one knows what the future may hold amid a volatile global order and conflicts playing out across the world.

In the future, the US and Russia may well sign a new nuclear weapons deal. But for the moment, the expiry of the treaty signals a more volatile and tense period.