Gen. Valeriy Zaluzhnyi is a national hero for Ukrainians after repelling the first wave of Vladimir Putin’s invasion on the outskirts of Kyiv.

But two years into the war, setbacks on the battlefield and political jealousies in the capital have soured his relationship with President Volodymyr Zelenskyy. This week, the president tried — and failed — to force out his commander-in-chief, pulling back the curtain on a damaging rift at the heart of the Ukraine war effort.

Their dispute helps explain the indecision over military strategy that is worrying officials in Washington and adds an unwanted element of uncertainty at a point when U.S. military aid hangs in the balance, troops are running dangerously short on ammunition and Russia is on the offensive again.