Asia is contemplating a growing nuclear future

Eighty years ago this August, the US bombed Hiroshima and Nagasaki, killing tens of thousands of people. Those acts helped to end World War II but also ushered in the nuclear age.

In 2025, a new atomic arms race is stirring, this time not provoked by Russia, China or North Korea — who have been ramping up their arsenals —  but instead by President Donald Trump's trade war, and his threats to withdraw the US defense umbrella. The result is a world growing more dangerous, not just for Asia, but for Americans too. 

The security architecture that helped prevent conflict from weapons of mass destruction is at risk of unravelling. For decades, Asian nations have relied on Washington's commitment to deterrence. That's no longer guaranteed. 

Long-time US allies, like Japan and South Korea, are calculating the cost — both economic and political — of developing their own arsenals. India and Pakistan both have a growing supply of warheads, potentially inflaming an already volatile conflict made worse by recent tensions in Kashmir. 

Trump insists that Washington has received the short end of the stick from defense deals, and that America's protection is keeping the world safe while other economies benefit more. He has a point — but is also ignoring historical lessons.

The aftermath of Washington's atomic bombings prompted a recognition that such a tragedy must be avoided at all costs. So deep was the soul-searching in American society that the goal of every US president since Harry Truman has been to limit rather than encourage the spread of these weapons rather than encourage them. Much of this was achieved through negotiated agreements and treaties. 

The policies have worked. Only nine countries now possess such arsenals, even though many more have the ability to build a bomb. But Trump is ushering in a more dangerous era. On the campaign trail in 2016, he suggested that Japan and South Korea might need to develop their own capabilities. Comments like that are influencing public opinion. A 2024 survey by the Korea Institute for National Unification showed six in 10 South Koreans now favor having them.

If Seoul opts for homegrown nukes, this would lead to a domino effect, note associate professors of political science at St. Francis Xavier University, Jamie Levin and Youngwon Cho. Japanese public sentiment has been deeply opposed because of the nation's painful past, but it has a full nuclear fuel cycle, allowing it in theory to fashion thousands of bombs in as little as six months, according to experts. 

India and Pakistan are among the most worrying players. The risk of a conflict increased this week after a terrorist attack in Kashmir killed dozens in some of the region's worst violence in years. So far, they have stuck to diplomatic measures as retaliation, but there is always the concern of escalation. 

Even in Southeast Asia, a relative safe zone, the risks have become much more pronounced. The 1995 Treaty of Bangkok established a Southeast Asian Nuclear Weapons Free Zone, banning members from development, manufacture, acquisition or possession. But if larger nations ramp up their arsenals, the spillover effect in Southeast Asia could force others to either look into developing their own technology, or find a new defense umbrella. Washington's unpredictability has created a leadership vacuum that Beijing will be keen to fill. 

Rather than failing to offer credible security guarantees, the US should engage with governments in Asia and address their defense ambitions. Under the Biden administration, a bilateral initiative called the Nuclear Consultative Group in 2023 was launched with Seoul, which helped to quell some anxiety. Efforts like this should be expanded to other allies like Japan. 

Convincing countries to stick with US deterrence strategies would be wise. Smaller nations watch what bigger countries do, not what they say. The US still has the opportunity to play global stabilizer and shouldn't cede that role to China. 

The world once looked to Washington to keep it safe. In 2025, that trust is fraying. It's in America's interest — not just Asia's — to rebuild it. 

Karishma Vaswani is a Bloomberg Opinion columnist covering Asia politics with a special focus on China. 

Disclaimer: This article first appeared on Bloomberg, and is published by special syndication arrangement.