Why the Ukraine-US divergence may deepen

For Ukraine, perhaps the only challenge equal to waging war against its enemy on the battlefield is managing tensions with its friends away from it. On Monday, the Belgorod region came under attack in one of largest cross-border raids into Russia over the course of the war. Two pro-Ukraine and anti-Kremlin Russian groups, the Russian Volunteers Corps (RDK) and the Liberty of Russia Legion (FRL), have claimed responsibility.

While Ukrainian Presidential Advisor Mykhailo Podolyak tweeted that his nation had “nothing to do with it” and that instead an “armed guerrilla movement” was opposing...