WHEN Russia flew nearly two dozen drones into Polish airspace on the night of September 9-10th, the NATO alliance proved very good at shooting bad things down. Forces from Germany, Italy, the Netherlands and Poland jointly deployed fighter jets, helicopters, missile batteries and an advanced surveillance plane. Several lumbering, unmanned intruders were destroyed, with no casualties on the ground. It was one of the largest incursions into NATO territory in the history of the alliance, and Europeans can be relieved that their defences worked. They should worry more, though, that Russia dared to test them in the first place.