In the contested waters of the Baltic Sea, a Danish military helicopter conducting lawful surveillance of a Russian frigate was met not with radio contact, but with flares — a deliberate act that Denmark's prime minister called reckless intimidation. The episode, unfolding the same day NATO jets downed a drone over Lithuania, speaks to a broader and accelerating pattern: Russia testing the edges of acceptable conduct along NATO's eastern frontier, one provocation at a time. What is at stake is not merely airspace or protocol, but the slow erosion of the thresholds that have long kept confronta