Global Nuclear Tensions Surge as Arms Control Treaties Collapse

Global nuclear tensions are rising as key arms control agreements collapse. The last major treaty between the U.S. and Russia expired earlier this year, leaving no formal limits on their arsenals. Meanwhile, other nuclear powers are expanding and upgrading their weapons, raising concerns about stability and oversight. The New START treaty, which capped U.S. and Russian nuclear stockpiles, lapsed in February 2025 without renewal. For the first time in decades, no arms control deal now exists between the two largest nuclear powers. Both nations continue modernising their arsenals, while China also accelerates its own nuclear expansion.

The Nuclear Non-Proliferation Treaty (NPT) faces growing strain. Russia’s repeated attacks on Ukrainian nuclear facilities, Iran’s unresolved nuclear activities, and U.S. military actions have weakened trust in the agreement. The 2025 NPT review conference ended without a joint declaration—the third time this has happened. Oversight in Iran has collapsed since U.S. and Israeli strikes in June 2025. The International Atomic Energy Agency (IAEA) can no longer conduct on-site inspections, leaving only remote monitoring and satellite imagery as limited alternatives. Without inspections, the risk of undeclared nuclear activity grows. Beyond the U.S. and Russia, France and the UK are also upgrading their nuclear capabilities. The absence of inspections, expired treaties, and ongoing modernisation efforts create a more unpredictable and volatile security landscape.

The end of New START and the breakdown of NPT negotiations mark a shift in global nuclear governance. With no active arms control agreements between major powers and reduced oversight in critical regions, the risk of unchecked nuclear development increases. Remote monitoring remains the only option where inspections have stopped, but its limitations leave gaps in verification.