The week has ended disastrously for Volodymyr Zelensky. A trip to Washington that was meant to ease tensions instead descended into a televised shouting match with Donald Trump and J.D. Vance in the Oval Office. The breakdown in relations raises two questions. Could Mr Trump now truly abandon Ukraine? Will Mr Zelensky feel forced to resign to save his country? One outcome, at least, is clear: this is a boost for Vladimir Putin.