What happens if Putin goes nuclear in Ukraine? Biden has a choice to make

Russian forces are in retreat yet Nato still holds back for fear of what a humiliated Kremlin might do. But now is precisely the time to step up the pressure

There has been much excited talk of a turning point" following Ukraine's rapid military advances in north-eastern Kharkiv region and what Kyiv cheerily calls its de-occupation" by fleeing Russians. Less comforting for the western democracies is an alternative theory: that the war is approaching a moment of maximum danger".

Worries that a cornered, desperate Vladimir Putin may resort to nuclear, chemical or biological weapons have resurfaced in the US and Europe, along with the argument, articulated by France's Emmanuel Macron, that Russia's president, despite his terrible crimes, should not be humiliated" - and allowed a way out.

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