What was Vladimir Putin thinking? Viewed from the west, the Russian president’s decision to authorise an undercover campaign to destabilise the US presidential election looks risky, even bizarre.

But, viewed through the prism of Russian history, the idea that a foreign intelligence operation could wreck the political system of an adversary is unremarkable. The birth of the Soviet Union, the state that Mr Putin once faithfully served, was midwifed by such an operation. During the first world war, the Germans facilitated Lenin’s return to Russia, knowing that the Bolshevik leader advocated peace between Russia and Germany. The aim was to destabilise the Tsarist regime, and to knock Russia out of the war. It succeeded brilliantly.

A century later, Mr Putin got behind the campaign of Donald Trump for reasons that were not a million miles from the German motivation for backing Lenin. The Russian president hated the sanctions imposed on his country after its annexation of Crimea in 2014. He associated this policy with Hillary Clinton. And he knew that Mr Trump supported rapprochement with Russia.