NATO is already intervening - they supply the weapons and ammo.
More recently "military advisors" in country
German military officials talking about how they can deflect blame if they program coordinates of Kerch Bridge into the Taurus Missiles.
Not every NATO country wants to go to war in Ukraine so it will be a "coalition of the willing" check the countries that have actually signed bilateral "security guarantees" with Ukraine in the last 6 months and you have your participants; Biden has said no US troops to go fight in Ukraine (but has sent advisors) so his hands are more or less tied till the election maybe?
