The New Strategic Arms Reduction Treaty, or New START, which caps the number of strategic nuclear warheads that the United States and Russia can deploy, and the deployment of land- and submarine-based missiles and bombers to deliver them, is due to expire on February 5, 2026.
It is the last remaining pillar of nuclear arms control between the world’s two biggest nuclear powers.
I think you will find no nuclear threats have been made that weren’t responses to threat themselves.