Continued support for Kyiv could exhaust Russia and allow Ukraine to retake its territories, but a dragged-out war could cause waning interest and increased debate in the mounting cost of aid among Ukraine’s allies, analysts said. 

A woman waves a huge Ukrainian flag during rally to mark the 32nd anniversary of Ukraine's independence and to protest against Russia's invasion of Ukraine, in Berlin, Germany, Aug. 24, 2023. (AP Photo/Markus Schreiber)

As Ukraine pushes on with a gruelling counteroffensive to recapture territory more than 18 months after Russia’s invasion, observers say international support is crucial to sustaining Kyiv’s resistance and momentum.

Since a June campaign to retake territory from Russian forces in the eastern and southern parts of t...