Russia planning 'grey zone operations'? Why is Europe intuitively spooked

Much of what worries Western officials is not a tank invasion but something harder to pin down. Drones drifting into Baltic airspace, sabotage at airports, cyberattacks, plots involving criminal networks operating far from Russia's own territory. Individually, each incident can be denied or dismissed as an accident but likely form a pattern that lets Moscow probe Nato's resolve without technically starting a war.