In the past few months, there have been a number of provocative events between Russia and the West: Russian jets buzz US warships in the Black Sea. Turkey, a NATO member, shoots down a Russian warplane involved in the Syria conflict. Russian government media talk publicly about turning the United States to ashes. NATO and Russia both reposition military assets and conduct exercises reminiscent of the darkest days of the Cold War. All this raises fear that misplaced bravado and brinksmanship could lead to the use of nuclear weapons. But there is a subtler, easily overlooked trend as well, which could make the situation even worse: a gradual blurring of the line – particularly in Russia – that separates conventional weapons and their delivery systems from their nuclear counterparts. Uncertainty about the actual capability of a weapon system can be a significant factor in managing a conflict, whether political or military. This is probably the calculation behind a number of Russian programs that are particularly vague about their nuclear dimension.