Even by his standards, Donald Trump’s latest volte-face on Ukraine was fast. He began last week touting a summit with Vladimir Putin to discuss a ceasefire in Russia’s war. By the end, he had called off the summit and stiffened US measures on Russia’s economy for the first time in his second presidency, taking a step the Biden administration had always balked at: imposing sanctions on Russia’s largest oil companies, Rosneft and Lukoil. Combined with further EU curbs on Russian energy they constitute a powerful blow to Moscow’s war economy.

Trump’s patience with Putin snapped, again, after the Kremlin rejected US calls for a ceasefire along the current front lines days after the two men spoke by phone. The US president responded this time with a significant shift in his efforts to bring the Russian president to the table. His administration, like the last, had feared targeting Russian oil exporters could cause a damaging price increase. A recent moderation in global prices, and hopes that Gulf producers Trump has been wooing would be ready to pump more, seems to have given the White House confidence to act.

Together with Russia’s third and fourth biggest producers, Gazprom Neft and Surgutneftegaz, targeted in the last days of the Biden White House, the US has now blacklisted Russia’s top four oil companies, accounting for about four-fifths of its oil exports.