The lack of visible senior Trump administration participation was the latest sign of how Washington has backed off during a critical juncture for Ukraine.

Foreign leaders will gather in Kyiv on Aug. 24 as Ukraine’s allies hold Coalition of the Willing talks and reaffirm support for Kyiv.

As Ukraine marks 35 years of independence on 24 August, international allies are expected in Kyiv in a show of solidarity. Whether the US envoys will join them remains uncertain.…