The last US-Russia nuclear treaty has ended – should the world worry?

Key Takeaway: The New START treaty, the final nuclear arms pact between the US and Russia, has expired, leaving the world’s two largest nuclear powers without any limits on their arsenals for the first time in decades.

The expiration on February 5, 2023, marks a major setback for global arms control and raises the spectre of a renewed nuclear arms race.

What Was the New START Treaty?

Signed in 2010, the New Strategic Arms Reduction Treaty (New START) was a cornerstone of nuclear stability. It placed strict caps on the number of deployed strategic nuclear warheads and the missiles and bombers that could deliver them. A crucial element was its verification system, which allowed for mutual on-site inspections and regular data exchanges, providing a vital window of transparency.

Why Did the Treaty Expire?

Despite months of negotiations, the US and Russia failed to agree on an extension. Talks collapsed over deep-seated disagreements, primarily fuelled by the ongoing war in Ukraine and broader disputes over the future framework of arms control. This failure leaves a dangerous vacuum.

Implications of a Treaty-Less World

The consequences are profound and dual in nature:

• Risk of a New Arms Race: Both nations have already initiated programs to modernise and develop new nuclear weapons. Without treaty limits, there is nothing to stop a quantitative or qualitative build-up, potentially triggering a costly and dangerous spiral.
• Threat to Global Security: New START was a pillar of the global non-proliferation regime. Its collapse weakens international efforts to prevent other countries from seeking nuclear weapons and undermines the message that major powers are committed to disarmament.

What Happens Now?

While both Washington and Moscow have expressed a nominal commitment to continue dialogue, the path to a new agreement is unclear. The geopolitical rift is deep, and trust is at a historic low.

For now, the international community faces an anxious period of uncertainty, closely monitoring how the two nuclear superpowers manage their colossal arsenals in an era without rules.