On a Wednesday morning in September, a Russian military helicopter slipped 300 metres into Polish airspace for 42 seconds near Braniewo, then withdrew as quietly as it had come. NATO jets scrambled in response, but the deeper question the incident raises is not one of airspace law — it is one of intent. Poland reads the crossing not as error but as examination, a deliberate probing of how quickly an alliance will move to defend its own threshold. In the long arc of European security, such moments carry weight precisely because they are designed to accumulate.