Executive Summary

The United States’ forward deployment of new U.S. B61-12 gravity bombs* in Europe in July 2025 marked a drastic shift in NATO’s nuclear policy, which has been somewhat stagnant over the past 20 years. Russia’s persistent threats of using nuclear weapons against Ukraine and its supporters, and its deployment of tactical nukes in Belarus, have renewed the need for nuclear deterrence in Europe, despite wider commitments for disarmament. The extent of the B61-12 deployment on the continent and its timeline for completion remain unclear, but exercises with nuclear weapons will very likely increase across Europe as the U.S. and Russia modernise and share their nuclear arsenal with allies. Furthermore, President Donald Trump on 30 October 2025 announced a resumption of nuclear weapon testing by the Pentagon, perhaps signalling the start of a broader arms race with Russia and China.

Background: The B61-12 is a modernisation of the B61-4 gravity bomb, introducing more electronic safeties and steerable fins to extend the service life of stockpiles for 20 years.