This week began with four European leaders, standing defiantly in Kyiv alongside Volodymyr Zelenskyy, issuing an ultimatum to Vladimir Putin: sign a ceasefire now, or together with Donald Trump we will force you to do so, with sanctions and other tough measures.
Over the subsequent days, there followed a series of offers, counter-offers, ultimatums and deflections, in a dizzying week of high-stakes diplomacy that often seemed to resemble a geopolitical poker game.
