There are just two roads out of Bakhmut for Ukrainian troops. Russian forces are within rocket range of both of them. And that means that, after nine months of brutal fighting, the battle for Bakhmut is entering what could be its decisive phase. In the coming hours or days, it’s possible one of two things will happen. The Russians advance so close to the two roads that the Ukrainians retreat in order to avoid encirclement. Or the Ukrainians counterattack and push back the Russians. The former would resolve the long, awful fight over Bakhmut. The latter would prolong it. In...