Constanze Stelzenmüller, expert on German, European, and trans-Atlantic foreign and security policy and strategy at the Brookings Institution, gives Stop the World her short take on the remarkable sense of urgency that Europe is displaying in building its own security capabilities: “I've never seen anything like this in my life.”

Her longer answer is a superb dissection of the radical reorientation coming out of the Trump administration—what she calls a “Yalta 2.0”; the likelihood that much of the world might have other ideas, leading a frustration of Trump’s instincts; Europe’s shortening patience for the skulduggery of Hungary’s Viktor Orbán; its need to keep the US engaged in Europe’s security; and ultimately the proper sense that Europe has accepted the need to step up to defend Ukraine and itself over the longer term.

Her conclusion: “I think we might all have to sort of buckle our seat belts.”