A few of the leaders were said to have interrupted summer holidays to fly to the United States on less than 24 hours’ notice to meet with the Ukrainian leader.

It is quite possible that Monday's meeting in the White House could prove even more crucial to the future of Ukraine - and for all of Europe's security - than last Friday's US-Russia summit in Alaska. On the surface, that Putin-Trump reunion seemed to live down to every expectation.

As Ukrainian President Volodymyr Zelensky arrived at the White House on Monday, President Trump gestured to his all-black suit. “Best I have,” Zelensky said, according to a video posted on social media by a White House staffer.

From the moment Donald Trump greeted Volodymyr Zelenskyy outside the West Wing on Monday afternoon, there seemed to be less personal tension between the men compared with their public spat in late February.