In the face of Russia’s stunning recent losses in northeastern Ukraine, President Vladmir Putin has just announced the mobilization of 300,000 Russian reservists. These are conventional (i.e., nonnuclear) forces, but Putin used the occasion to lob nuclear threats: “In the event of a threat to the territorial integrity of our country and to defend Russia and our people, we will certainly make use of all weapon systems available to us. This is not a bluff,” he warned. “Those who are using nuclear blackmail against us should know that the wind rose can turn around.”