With its forces falling back before onslaughts in eastern Ukraine, Kiev agreed to the release of Russian paratroopers captured inside its borders last week in return for 63 Ukrainians who had crossed into Russian territory to flee fighting. The exchanges appeared to be a modest sign of a willingness to talk on the eve of cease-fire talks in Minsk, Belarus, on Monday that Ukrainian President Petro Poroshenko said could be decisive. Kiev has taken a hard line in previous talks as it sought to regain territory taken by Moscow-backed rebels. But after Russian troops openly intervened, reversing Kiev’s gains and leaving hundreds of its soldiers surrounded, Mr. Poroshenko may be preparing to make concessions. Moscow appeared to be hardening its demands and to be ready to press Kiev to accept outright secession of its two eastern provinces of Donetsk and Lugansk. In remarks broadcast on Russia’s state television, […]