European leaders are confronting their worst-case scenario: maybe they really are going to be dealing with a bellicose Russia alone.When the United States lined up alongside Russia and North Korea earlier this week to oppose a UN motion condemning Vladimir Putin’s invasion of Ukraine, some European officials knew that the transatlantic relationship was in deep trouble. Then they watched in horror as Donald Trump gave Volodymyr Zelenskiy a public dressing down in the Oval Office and something broke.