Explained: What the end of the New START treaty means for the world

For the first time in decades, the world has entered a moment with no binding limits on the two largest nuclear arsenals on the planet.

The New START treaty between the United States and Russia has expired, ending the last remaining agreement that capped strategic nuclear weapons and allowed for mutual inspections and transparency. What replaces it, if anything, remains unclear.

In this explainer, we break down what the end of New START really means, why this treaty mattered far beyond Washington and Moscow, and how its expiry could reshape global nuclear stability at a time of rising geopolitical tensions. From arms control and deterrence to missile defence and great power rivalry, the consequences extend well beyond the two countries involved.

This is not about speculation or panic, but about understanding what changes when long-standing guardrails disappear, and why the rest of the world is watching closely.