Since the fall of the Soviet Union, two doomsday scenarios have come to capture the imagination of the West. One is that, thanks to climate change, our planet will explode into a retributive blaze reminiscent of the Book of Revelation. The other is that we are on the cusp of inventing an artificial intelligence that will opt to destroy humanity after performing some impenetrable cost-benefit calculation.Our attitude to the threat posed by Vladimir Putin’s Russia, by contrast, borders on the flippant. It is striking that the Wagner Group’s abortive coup was greeted with neither trepidation nor a sober assessment of...