Ukraine’s allies now worry the war is dragging into a long fight that may strengthen Vladimir Putin’s hand as hopes fade that Kyiv’s forces will deliver a definitive breakthrough this year.

More than two months into its counteroffensive, Kyiv has so far managed to make only tactical advances against heavily dug-in Russian forces, despite having committed many of the units trained and armed by the U.S. and Europe for the operation. The window for further big actions is narrowing as wet and cold weather looms in the autumn.

Ukraine and its allies have vowed to keep up the fight as long as needed, but officials concede it will be a tall order to repeat the levels of massive support that made the current push possible. Stocks of ammunition in particular are depleted and production in the U.S. and Europe won’t be ramped up until late 2024. F-16 fighters likely won’t arrive until next year, either.