The dust-up over the fellowship program illustrates a broader phenomenon: Despite their mutual fury toward Putin, Ukrainian activists and Russian dissidents are largely avoiding each other. There’s little cooperation and no serious coalition building. Instead, there’s tremendous suspicion on the Ukrainian side and defensiveness from the Russians. The tensions suggest that no matter when the war ends, the social ruptures between Ukrainians and Russians will fester far longer. Russian dissidents simply aren’t doing enough to support Ukrainians, said Daria Kaleniuk, a Ukrainian anti-corruption activist. There’s no broad Russian dissident campaign to help Ukraine get NATO membership or funds from seized...