As the U.S. and Russia push ahead – so far without Ukraine at the table – on talks to end the war, political and military leaders in Europe are fleshing out details of a plan for European forces to help ensure Moscow does not attack again.

After months of quiet discussions, the proposal has become increasingly public. It will likely be on the agenda when British Prime Minister Keir Starmer and French President Emmanuel Macron, two major backers of the idea, visit Washington on separate days next week for talks with President Donald Trump.