In relation to Putin and Ukraine, it is NATO’s nuclear posture that is particularly relevant.  Developed in the 1960s and little changed since, it is known as “Flexible Response” and originally codified in a document, MC14/3, titled Overall Strategic Concept for the Defence of the NATO Area.   This was agreed in 1968 and held that if NATO was losing a conventional war with the Soviet bloc it would be prepared to use nuclear weapons first to prevent defeat.The Soviets claimed to have a “no first use” policy but given their huge range of tactical nuclear weaponry no one in NATO took this seriously.  Indeed, Putin’s threat of WMD use in Ukraine at the end of February was little more than a restatement of NATO’s first use policy.

If we extend this discussion to a more detailed assessment of UK tactical nuclear use, one of the clearest analyses is found in a 1994 article in the authoritative military journal, the International Defence Review. (10) This cited four levels of response in what it called the “usage spectrum”:

• In response to an opponent’s nuclear strike,
• a response to an opponent’s use of CBW,
• a demonstration role, possibly at a non-critical uninhabited area, or
• in a punitive role following a warning against an action.

Three of these four involve first use, the third being strikingly similar to Putin’s recent threat.

stopwar. The Looming Threat of Nuclear Weapons in the War in Ukraine | Stop the War