Putin’s nuclear threat shows a desperate man out of options | Simon Jenkins

Using such weapons has no tactical purpose - it would only lose the Russian president support at home and abroad

Vladimir Putin is ready to use a nuclear weapon in his ongoing attempt to conquer Ukraine. Or so says Vladimir Putin. The reason is that his conquest has been justly defeated so far and he sees no other way forward. The prospect of such an escalation is appalling. A line would be crossed. Nuclear-armed powers round the world would regard it as a licence. It might not be the end of the world, but it might just be the beginning of the end.

For all the cheerleading of western politicians over Putin's humiliation, it is crucial to emphasise how disciplined has been the west's support for Kyiv. Yes, Nato took a gamble in advancing its borders eastwards after 1991, George Kennan's most fateful error of the post-cold war era". It taunted Russia's paranoia and risked the emergence of a belligerent patriot, which is what happened in the case of Putin. But at no point has the west taken up arms against Russia, even when Russia successively attacked and repatriated" areas of neighbouring Georgia, Chechnya and even Ukraine.

Simon Jenkins is a Guardian columnist