During the Cold War, Moscow’s leverage depended on its military might. Today, vast reserves of oil and gas, lying between the hungry markets of Europe and East Asia, have taken over that role. The importance that Russia attaches to hydrocarbon diplomacy was underlined yesterday by President Dmitry Medvedev’s call for a formal demarcation of the territory that it claims under the Arctic Ocean. Its aggressive policy towards a region whose melting icecap offers access to possibly huge energy and mineral deposits was dramatically illustrated last year by the planting of a Russian flag on the seabed at the North Pole. The front line of the confrontation between Russia and the West has shifted from the North German Plain to the fossil fuel deposits that lie beneath Siberia and the Arctic.