WASHINGTON, DC — A major era of global safety officially ended last month, as the nuclear arms control treaty between the US and Russia known as New START expired without a replacement.
This marks the collapse of a 50-year framework that kept the world’s two largest nuclear powers in check. Russia and the US collectively hold 90% of the world’s nuclear weapons.
The downfall of New START was accelerated by the war in Ukraine. In 2023, Russia stopped participating in the treaty because of U.S. support for Kyiv. Mutual trust eventually evaporated.
However, the deadlock isn’t just about Moscow and Washington. The rise of China as a nuclear power changed the game. The US wanted China to join a new treaty, but Beijing refused, arguing its arsenal is still much smaller than those of the U.S. and Russia.
Moreover, 9 countries are significant competitors in the nuclear arms race, including India and Pakistan. The two countries appeared on the brink of exchanging nuclear fire last year.
Iran
In his State of the Union address Feb. 24, President Donald Trump indicated to the world that he would never allow Iran to develop a nuclear weapon.
“I will never allow the world’s number one sponsor of terror, which they are by far, to have a nuclear weapon,” said the President. “They have been warned to make no future attempts to rebuild their weapons program, and in particular, nuclear weapons. Yet they continue starting it all over.”
“They are at this moment again pursuing their sinister ambitions,” said Trump, setting the stage for the Feb. 27 US-Israel joint attack on Iran. The Bulletin of Atomic Scientists and other sources suggest that Iran has amassed over 400 kilograms of highly enriched uranium at 60%, which puts it one step closer to building nuclear weapons.
Green Light for North Korea
George A. Hutchinson, a former Air Force officer and editor of the International Journal of Korean Studies, explained the gravity of the moment, in an interview with American Community Media.
“The treaty’s lapse removes the last remaining pillar of over 50 years of nuclear control. While it wasn’t perfect, it provided stability and predictability. Now, the world is entering a much more competitive nuclear era with very few guardrails left to keep us safe.”
For the Korean Peninsula, the timing could not be worse. As global rules crumble, North Korea is moving fast to modernize its missiles and nuclear warheads.
In the past, the US and Russia worked together to stop nuclear proliferation. Those days are gone. Andrew Yeo, a senior fellow at the Brookings Institution, noted that while the treaty’s end doesn’t change North Korea’s Supreme Leader Kim Jong Un’s mind, it changes the world around him.
Permissive Environment
“The Kim regime wants to develop nuclear weapons regardless of what happens with New START. However, the failure to renew the treaty creates a ‘permissive environment.’ It makes it easier for countries like North Korea to keep building their programs without facing global pressure,” said Yeo.
Russia and China have already weakened UN sanctions. This gives North Korea an “open lane” to expand its long-range missile capabilities without fear of being stopped, said Hutchinson.
Weakening the Nuclear Umbrella
The collapse of the US-Russia order is causing a crisis of confidence for American allies. In South Korea, many people are asking: If the US is busy in a nuclear arms race with Russia and China, can it still protect us?
Because of this fear, more South Koreans are calling for “nuclear self-reliance”—the idea that South Korea should build its own nuclear weapons. According to an Asan Institute poll in March 2025, 76.2% of South Koreans support this idea.
Hutchinson points out that the pressure is growing. “Confidence in the long-term reliability of the US nuclear umbrella is being tested. This debate in Seoul could reach a tipping point as the global structures that once controlled nuclear weapons continue to fall apart,” he said.
However, Yeo emphasized that the U.S. commitment remains strong, even if the world is more dangerous. “The credibility of the U.S. nuclear umbrella remains unchanged. What has changed, however, are the stakes. The U.S. and South Korea need to work closer than ever because of the combined threats from Russia, China, and North Korea.”
The world has entered a “multipolar” nuclear age. Without the U.S. and Russia leading the way, it is much harder to demand that North Korea give up its weapons. As the “guardrails” disappear, the risk of a new arms race in East Asia is higher than it has been in decades.
