ALL of Europe rejoiced when the European Space Agency deposited Philae, a probe the size of a kitchen appliance, on the surface of a comet 300m miles (480m km) from the Earth. It was like throwing a dart blindfolded across an ocean and hitting the bullseye. Philae fell silent soon afterwards, but not before dispatching reams of data and a shot of optimism to a continent that has had little to cheer. Closer to home the European Union finds it harder to exert influence—even over its neighbourhood.Russia’s intervention in Ukraine is providing an early test for the EU’s new high representative for foreign policy, Federica Mogherini, who previously served (albeit briefly) as Italy’s foreign minister. NATO is warning of a renewed build-up of Russian troops and kit in eastern Ukraine. The recent sham elections in two pro-Russian separatist regions in the Donbas were “respected” if not recognised by Moscow. The Minsk ceasefire accords signed in September by Ukraine, Russia and the separatists are being honoured only in the breach. Petro Poroshenko, Ukraine’s president, is preparing for “total war”.How did Europe allow such devastation on its doorstep? EU officials cite…