Russia's Carrot-and-Stick Strategy

Russia has shown signs in recent days, particularly when it comes to Ukraine, that it is willing to compromise. But Russia's goodwill goes only so far. While it was discussing prisoner swaps with Kiev and delaying elections in separatist parts of eastern Ukraine, Russian warplanes were harassing U.S. vessels and aircraft in the Baltic and Black seas and Russian artillery units were moving to the battlefields of Aleppo. Moscow is also investing heavily in its nuclear force, alarming officials in Washington and threatening to undermine two decades of arms control efforts....