NATO can't act because Western "leaders" are collectively spineless and ineffectual. NATO now means Never Able To Operate. Like the United Nations, NATO is a pointless joke, an empty shell that costs money but serves no purpose and will ultimately collapse at the application of the slightest pressure. Russia has already (i) strafed a UK warship, and (ii) fired a Fox2 at a UK Tornado interceptor, and (iii) violated Polish airspace with its cruise missiles, as well as (iv) shot down a civilian airliner all the way back before the 2022 3rd invasion of Ukraine. And every time we've done nothing, because that's what we're best at. Too busy gorging on slop and gawping at our flickering shiny screens to notice we're on the Titanic and the water is already at knee-height.