In the fall, tensions in Washington reached a crescendo as Moscow made persistent nuclear threats and U.S. intelligence reported discussions among Russian military leaders about the use of such weapons.
Concerns remain over Russia using a nuclear weapon, but the tensions have since abated. Several factors explain why, officials said: A more stable battlefield, China’s warnings against the use of nuclear weapons, improved communications between Moscow and Washington, and an increased role of the International Atomic Energy Agency in Ukraine have contributed to a measure of stability.
President Vladimir Putin of Russia, a senior U.S. official said recently, may well have come to the conclusion that the threats, which he once saw as leverage, were backfiring.